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Background Milk and milk products often contribute a significant portion to the daily human diet and provide highly bioavailable animal proteins for maintenance and growth. Several processing technologies have the potential to affect the structural and functional properties of the milk proteins and can influence their fate in the gastrointestinal tract. Scope and approach The present review examines the thermal and non-thermal processing technologies that affect the digestibility of milk proteins and influence the behaviour of milk proteins within gastrointestinal digestion environments. We reviewed papers that have been published in the last five years on different aspects of milk protein digestibility. Key findings and conclusions Processing of milk and milk products can induce several modifications in the proteins that change their susceptibility to digestive enzymes in the gut. Several emerging nonthermal technologies, such as high-pressure, ultrasound, pulsed light, microfluidization and microfiltration, have been reported to induce protein structural changes which can cause denaturation, conformational changes and unfolding of the proteins, thereby increasing their susceptibility to enzymatic hydrolysis. Thermal processing technologies, such as ohmic heating, microwave and pasteurization, also have potential to induce protein structural and conformational changes which can affect their digestive behaviour during gastrointestinal digestion. Some of these processing technologies have been reported to increase the susceptibility of milk proteins that are otherwise resistant to gastric or intestinal digestion and can reduce the allergenicity of the milk proteins. The present review examines in detail the underlying mechanisms of how different thermal and non-thermal technologies mediate the digestibility of milk proteins. Expanding our understanding of the digestion of milk proteins has commercial potential and could increase opportunities for the application of milk proteins.

Background and Aims Although most proteins and a significant proportion of phenolic substances are extracted from grape pulp, the extraction of grape skin components may contribute to and modulate the final concentration of these components in juice. This study investigated the influence of skin contact time and various extractants on the extraction of Sauvignon Blanc grape skin components. Methods and Results Two trials were conducted. The first evaluated the impact of skin contact time on the extraction of phenolic substances and proteins from grapes (fresh vs chilled) into juice. The juice with 24 h skin contact showed a significantly higher concentration of phenolic substances and chitinases, but not of thaumatin‐like proteins. No difference was observed between fresh and chilled berries. The second trial evaluated the extractability of phenolic substances and proteins from grape skin (ground vs peeled) using different extractants. More phenolic substances and tannin were extracted using ground skin powder as greater mechanical damage assisted in the extraction of skin components. Compared to mechanically crushed and pressed grape juice, hand squeezed juice showed a lower protein concentration and the presence of tannin. It is suggested that hand squeezing was more effective in extracting components (mainly phenolic substances) from grape skin, but mechanically crushing and pressing was more effective in extracting components (mainly proteins) from grape pulp. Extractants containing bovine serum albumin or protein resulted in a lower concentration of phenolic substances and tannin in the extracts, and the concentration of bovine serum albumin and protein was dramatically decreased after extraction. Conclusion This study confirmed that longer skin contact increased the extraction of skin phenolic substances. Longer skin contact also increased the protein concentration in juice, particularly the pathogenesis‐related proteins, but it can be modulated by the co‐extraction of phenolic substances. Significance of the Study This study improves our current understanding of interactions between phenolics and proteins during grape processing, which can be used as a tool for winemakers to manage the extraction of these compounds into juice.

Thermal processing is an inevitable part of the processing and preparation of meat and meat products for human consumption. However, thermal processing techniques, both commercial and domestic, induce modifications in muscle proteins which can have implications for their digestibility. The nutritive value of muscle proteins is closely related to their digestibility in the gastrointestinal tract and is determined by the end products that it presents in the assimilable form (amino acids and small peptides) for the absorption. The present review examines how different thermal processing techniques, such as sous-vide, microwave, stewing, roasting, boiling, frying, grilling, and steam cooking, affect the digestibility of muscle proteins in the gastrointestinal tract. By altering the functional and structural properties of muscle proteins, thermal processing has the potential to influence the digestibility negatively or positively, depending on the processing conditions. Thermal processes such as sous-vide can induce favourable changes, such as partial unfolding or exposure of cleavage sites, in muscle proteins and improve their digestibility whereas processes such as stewing and roasting can induce unfavourable changes, such as protein aggregation, severe oxidation, cross linking or increased disulfide (S-S) content and decrease the susceptibility of proteins during gastrointestinal digestion. The review examines how the underlying mechanisms of different processing conditions can be translated into higher or lower protein digestibility in detail. This review expands the current understanding of muscle protein digestion and generates knowledge that will be indispensable for optimizing the digestibility of thermally processed muscle foods for maximum nutritional benefits and optimal meal planning.

Hexaploid Caucasian clover was grown in soil sampled at three New Zealand South Island high country sites to which specific rhizobium inoculum had been added with sowing of the legume in 1975, 1992...

Grape proteins, particularly pathogenesis-related (PR) proteins, are responsible for white wine haze formation which is of great concern to winemakers. Phenolic substances in grapes have also been reported with involvement in protein haze formation by interaction with proteins. The protein and phenolic substances in grapes are important in determining their concentrations in juice and resultant wine, and thus consequent wine protein stability. This study investigated the changes in these haze formation related components in ‘Sauvignon Blanc’ grape skin and pulp during ripening. The phenolic content on per berry basis generally increased in grape skin and pulp, but the phenolic concentration on per gram of berry basis showed a decreasing trend in grape skin, suggesting the accumulation effect of phenolics in skin is less than the dilution effect caused by berry growth. Tannin was only detected in grape skin but not in the pulp and the changes in tannin were similar to total phenolics. PR proteins were synthesized and accumulated along with the increase of total soluble solids (TSS) in both skin and pulp from veraison until harvest during ripening. The increase of PR proteins in grapes during ripening was also reflected in corresponding juice. The results suggested most of PR proteins in juice is likely extracted from grape pulp, and the riper the grapes the more PR proteins may be extracted into juice. The higher level of phenolics in riper grapes could increase the extraction of phenolics into juice and thus decrease the final concentration of PR proteins.

Although the bioactivities of bovine lactoferrin have been extensively investigated, little is known about deer milk lactoferrin bioactivity and its amino acid sequence. This research investigated the amino acid sequence of deer lactoferrin and the antimicrobial activities of two lactoferrin-encrypted peptides, lactoferricin (Lfcin) and lactoferrampin (Lfampin). Deer lactoferrin was found to have a molecular weight of 77.1 kDa and an isoelectric point of 7.99, which are similar to that of bovine lactoferrin, 78 kDa and pI 7.9. Deer lactoferrin contains 707 amino acids, one amino acid less than bovine lactoferrin, and has 92% homology with bovine lactoferrin. Deer lactoferricin exhibited strong antimicrobial activity against E. coli American Type Culture Collection (ATCC) 25922 and L. acidophilus ATCC 4356. The antimicrobial activities of deer and bovine Lfcin and Lfampin were compared. Based on MIC, deer Lfcin was found to be a more effective inhibitor of L. acidophilus ATCC 4356 than bovine Lfcin, but bovine Lfcin and Lfampin were more effective against E. coli ATCC 25922 than deer Lfcin and Lfampin. The deer Lfcin sequence differed at seven amino acids from bovine Lfcin and this decreased the net positive charge and increased the hydrophobicity. Deer Lfampin contained two differences in amino acid sequence compared to bovine Lfampin which decreased the net positive charge. These amino acid sequence differences likely account for differences in antibacterial activity. Positive charge and hydrophobic residues provide the amphipathic character of these helical peptides, and are considered important for binding of antimicrobial peptides. In silico modelling of deer Lfcin indicated an identical α-helical structure compared to bovine Lfcin.

An alkaline extraction method has been used in many studies to extract total protein from cereal samples. Wheat bran protein concentrate (WBPC), oat bran protein concentrate (OBPC), and barley protein concentrate (BPC) were prepared by alkaline extraction and isoelectric precipitation to study their functional and nutritional properties. The three protein concentrates were hydrolysed by an in vitro pepsin-pancreatin digestion model. Their digestibility (%) and degree of hydrolysis (DH%) were evaluated, and SDS-PAGE electrophoresis was used to illustrate the protein and peptides patterns. The change of the particle sizes and the release of the essential amino acids was followed during the digestion process. The in vitro digestibility of WBPC, OBPC and BPC was 87.4%, 96.1% and 76.9%, respectively. The DH% of protein concentrates were between 50 and 60%. The change of the particle size distribution values Dv(50) was assumed to be related to protein aggregations during the digestion. The protein fractions were identified and the degradation during the digestion and were analysed by SDS-PAGE; the gels of WBPC and OBPC digestion showed virtually complete degradation whereas the intensive bands of undigested protein were presented for BPC. The generation of the free amino acids and short chain peptides were significantly higher at the end of the intestinal digestion compared to the stages of before and after gastric digestion. Higher content of the deficient amino acids such as lysine and threonine were found comparing to the level of deficient amino acids in cereal grains but does not meet the daily recommended intake.

Meat proteolytic systems play a crucial role in meat tenderisation. Understanding the effects of processing technologies and post-mortem storage conditions on these systems is important due to their crucial role in determining the quality characteristics of meat and meat products. It has recently been proposed that tenderisation occurs due to the synergistic action of numerous endogenous proteolytic systems. There is strong evidence suggesting the importance of μ-calpain during the initial post-mortem aging phase, while m-calpain may have a role during long-term aging. The caspase proteolytic system is also a candidate for cell degradation in the initial stages of conversion of muscle to meat. The role of cathepsins, which are found in the lysosomes, in post-mortem aging is controversial. Lysosomes need to be ruptured, through aging, or other forms of processing to release cathepsins into the cytosol for participation in proteolysis. A combination of optimum storage conditions along with suitable processing may accelerate protease activity within meat, which can potentially lead to improved meat tenderness. Processing technologies such as high pressure, ultrasound, and shockwave processing have been reported to disrupt muscle structure, which can facilitate proteolysis and potentially enhance the aging process. This paper reviews the recent literature on the impacts of processing technologies along with post-mortem storage conditions on the activities of endogenous proteases in meat. The information provided in the review may be helpful in selecting optimum post-mortem meat storage and processing conditions to achieve improved muscle tenderness within shorter aging and cooking times.

Lactoferrin (Lf) and other whey proteins have been isolated from red deer milk for the first time using a three-step anion and cation exchange chromatography protocol. The separated deer Lf was subject to in vitro gastric and duodenal digestions to generate peptides. The purity of the deer Lf and its hydrolysis products were analyzed by SDS-PAGE. The antibacterial activity of the deer Lf and its hydrolysates were investigated and was compared to cow counterpart. Gastric and duodenal digested deer Lf had strong bactericidal activity against E. coli ATCC 25922 with minimum inhibition concentration (MIC) of 280 &micro, M and 402 &micro, M, respectively. These results suggest that deer milk contains bioactive whey proteins and can generate bioactive peptides, which can benefit human health by inhibiting food-borne pathogenic bacteria.

Lactoferrin (Lf) and other whey proteins have been isolated from red deer milk for the first time using a three-step anion and cation exchange chromatography protocol. The separated deer Lf was subject to in vitro gastric and duodenal digestions to generate peptides. The purity of the deer Lf and its hydrolysis products were analyzed by SDS-PAGE. The antibacterial activity of the deer Lf and its hydrolysates were investigated and was compared to cow counterpart. Gastric and duodenal digested deer Lf had strong bactericidal activity against E. coli ATCC 25922 with minimum inhibition concentration (MIC) of 280 µM and 402 µM, respectively. These results suggest that deer milk contains bioactive whey proteins and can generate bioactive peptides, which can benefit human health by inhibiting food-borne pathogenic bacteria.

The effects of egg white protein and soy protein isolate addition on the nutritional and digestibility of gluten-free pasta based on banana flour were studied. The level of protein additions (soy protein or egg white protein) were 0, 5, 10 and 15% of banana flour (w/w). Pasta made from 100% durum wheat semolina was used as a control. Soy protein isolate inclusion into banana pasta increased total phenolic content (TPC) and antioxidant capacities, while egg white protein decreased the TPC and antioxidant capacities with the increasing level of addition. Starch digestibility was affected by the type of protein addition. Egg white protein lowered starch digestibility compared to soy protein isolate. Protein inclusion in banana pasta also altered protein digestibility, amino acid profiles and protein digestibility-corrected amino acid score (PDCAAS). Soy protein isolate increased protein digestibility of gluten-free pasta compared to egg white protein. Protein enrichment gave better amino acid profiles of banana pasta compared to semolina pasta with egg white protein and performed a better PDCAAS compared to soy protein isolate. These results showed that soy protein isolate and egg white protein addition enhanced nutritional qualities and digestibility properties of gluten-free banana pasta.

The tenderization process, which can be influenced by both pre- and post-slaughter interventions, begins immediately after an animal's death and is followed with the disruption of the muscle structure by endogenous proteolytic systems. The post-slaughter technological interventions like electrical stimulation, suspension methods, blade tenderization, tumbling, use of exogenous enzymes, and traditional aging are some of the methods currently employed by the meat industry for improving tenderness. Over the time, technological advancement resulted in development of several novel methods, for maximizing the tenderness, which are being projected as quick, economical, nonthermal, green, and energy-efficient technologies. Comparison of these advanced technological methods with the current applied industrial methods is necessary to understand the feasibility and benefits of the novel technology. This review discusses the benefits and advantages of different emerging tenderization techniques such as hydrodynamic-pressure processing, high-pressure processing, pulsed electric field, ultrasound, SmartStretch™ , Pi-Vac Elasto-Pack® system, and some of the current applied methods used in the meat industry.

Research was conducted to investigate the effects of egg white protein and soy protein powder addition on physicochemical properties of banana pasta. The levels of protein fortification were 5, 10, and 15% of banana flour (w/w) for each type of protein. Pasta made from 100% of durum wheat semolina and 100% of banana were used as controls. The addition of soy or egg white protein showed significant differences on physicochemical properties compared with semolina pasta and pure banana pasta. Type of protein, level of protein, and the interaction between type of protein and the level of protein altered protein content. Soy protein gave higher protein content than egg white protein, whereas higher level of protein addition gave higher protein content of pasta. The fortified banana pasta had higher protein content than semolina pasta. There were no significant effects of soy or egg white protein addition to either insoluble or soluble dietary fiber content. It was also observed that the cooking properties of pasta (optimum cooking time, swelling index, water absorption index, and cooking loss) were affected by the level of protein addition and the type of protein. Textural analysis for tension and firmness of the pasta illustrated that protein fortification improved the textural characteristic of banana flour pasta. The addition of soy or egg white protein also improved the protein content of banana pasta making it equal to or even better than semolina pasta. PRACTICAL APPLICATIONS: Research has been carried out to improve gluten‐free products, not only for people with celiac diseases, but also for those who choose a healthy lifestyle. Gluten‐free ingredients are challenging to work with as they cannot create a sufficiently strong binding network between their proteins and starch in the dough, especially in some products such as pasta products. The use of an additional protein source has the ability to improve the product quality and contribute to the nutritional values which can give added value to the final gluten‐free pasta product. This study reports the effects of the level of egg and soy protein fortification on the physicochemical properties of banana pasta. To the best our knowledge, there is no study which tried to develop banana pasta with protein addition alone such as soy protein isolate or egg protein powder.

Defined as meat cultured in a laboratory within a bioreactor under controlled artificial conditions, in vitro meat is a relatively recent area that has opened a whole universe of possibilities and opportunities for the meat sector. With improved chemical and microbial safety and varied options, in vitro meat has been proposed as a green, healthy, environmentally friendly, and nutritionally better product that is free from animal suffering and death. Cell culture and tissue culture are the most probable technologies for the development of this futuristic muscle product. However, there are many challenges in the production of a suitable product at an industrial scale under a sustainable production system and a great body of research is required to fill the gaps in our knowledge. Many materials used in the product development are novel and untested within the food industry and demand urgent regulatory and safety assessment systems capable of managing any risks associated with the development of cultured meat. The future of this product will depend on the actions of governments and regulatory agencies. This article highlights emerging biotechnological options for the development of cultured meat and suggests ways to integrate these emerging technologies into meat research. It considers the problems and possibilities of developing cultured meat, opportunities, ethical issues as well as emerging safety and regulatory issues in this area.

Tenderness in one of the most important aspects of meat quality particularly for beef, lamb and pork. Aging at refrigerated temperatures allows proteases within the muscle to break up the structure of the myofibrils and tenderises the meat. Calpain 1, a calcium-dependent cysteine protease, is the key enzyme involved and it is activity is regulated by a specific inhibitor, calpastatin. Aging is a complex process and involves other proteases including caspases, cathepsins and calpain 2 and 3. The activity of all of these is modulated by the physical conditions and other proteins within the muscle. Aging does not lead to proteolysis of the connective tissue, which is responsible for the background toughness of different muscles, and exogenous proteases such as papain and actinidin are needed to hydrolyze collagen.

Food ingredients commonly undergo heat treatment. Meat, in particular, is typically consumed after some form of heating, such as boiling or roasting. Heating of meat can introduce a wide range of structural changes in its proteinaceous components. At the 3-dimensional structural level, meat proteins may denature and form aggregates upon heating. At the molecular level, primary structure (amino acid residue) alterations reported in cooked meat include protein carbonylation, modification of aromatic residues, and the formation of Maillard reaction products. Identification of these modifications is essential for determining the mechanism of thermal processing of meat and allowing better control of the nutritional and functional properties of products. This article reviews and summarizes the current state of understanding of protein modifications at the molecular level in commonly consumed mammalian food. In addition, relevant case studies relating to characterization of heat-induced amino acid residue-level modifications in other biological materials such as milk and wool are discussed to provide complementary insights.

Background and Aims Ultraviolet (UV) radiation and powdery mildew infection could increase the concentration of phenolic substances and proteins in grape berries. This study investigates the changes in the composition of Sauvignon Blanc grapes in response to UV exclusion and to powdery mildew infection, and any consequential influence on the extraction of pathogenesis-related (PR) proteins into juice which may influence bentonite requirement for wines. Methods and Results Exclusion of UV and powdery mildew infection treatments was applied to potted grapevines grown in a glasshouse. For all treatments, grape skin, pulp and extracted juice were analysed for the concentration of phenolic substances and proteins. The UV exclusion treatment resulted in a lower concentration of phenolic substances, tannins and PR proteins in grape skin, but had no effect on the PR proteins in pulp. Powdery mildew infection of grapes resulted in a significant increase in PR proteins in grape skin and pulp but had no impact on tannins in skin. A lower concentration of PR proteins was observed in the corresponding juice from the control of the UV exclusion experiment. The significantly higher concentration of PR proteins in grapes from the high powdery mildew infection treatment was reflected in the resultant juice. Conclusions Powdery mildew infection and UV exclusion have a significant impact on the composition of Sauvignon Blanc grapes. The concentration of PR proteins in juice is predominantly determined by their concentration in grape pulp, but their concentration in grape skin and interactions with phenolic substances/tannins during the juicing process may modulate their final concentration in juice. Significance of the Study Pathogenesis-related proteins are the main cause of haze formation in finished white wine. The findings presented here contribute to an improved understanding of the variable concentration of PR proteins in juice and resultant wine, and hence the variation in bentonite requirement.

This Data article provides Supplementary data related to the research article titled “In-depth characterisation of the lamb meat proteome from longissimus lumborum ” by Yu et al. [1] . This research article reports the proteome catalogue of the 48 h post-mortem lamb longissimus lumborum. A list of 388 ovine-specific proteins were identified and characterised after separating the samples into sarcoplasmic, myofibrillar and insoluble fractions, followed by an in-depth shotgun proteomic evaluation and bioinformatic analysis. The detailed list of identified proteins, the annotated MS/MS spectra corresponding to the proteins identified by a single peptide-spectrum match, the raw Gene Ontology annotation data and other miscellaneous files, as will be described below, were contained in this Data article. We hope the data presented here will contribute to the current knowledge of the global protein composition of lamb skeletal muscle/meat.

Thaumatin-like proteins (TLPs) and chitinases are the two main groups of pathogenesis-related (PR) proteins found in wine that cause protein haze formation. Previous studies have found that phenolics are also involved in protein haze formation. In this study, Sauvignon Blanc grapes were harvested and processed in two vintages (2011 and 2012) by three different treatments: (1) hand harvesting with whole bunch press (H-WB); (2) hand harvesting with destem/crush and 3 h skin contact (H-DC-3); and (3) machine harvesting with destem/crush and 3 h skin contact (M-DC-3). The juices were collected at three pressure levels (0.4 MPa, 0.8 MPa and 1.6 MPa), some juices were fermented in 750 mL of wine bottles to determine the bentonite requirement for the resulting wines. Results showed juices of M-DC-3 had significantly lower concentration of proteins, including PR proteins, compared to those of H-DC-3, likely due to the greater juice yield of M-DC-3 and interactions between proteins and phenolics. Juices from the 0.8–1.6 MPa pressure and resultant wines had the highest concentration of phenolics but the lowest concentration of TLPs. This supported the view that TLPs are released at low pressure as they are mainly present in grape pulp but additional extraction of phenolics largely present in skin occurs at higher pressing pressure. Wine protein stability tests showed a positive linear correlation between bentonite requirement and the concentration of chitinases, indicating the possibility of predicting bentonite requirement by quantification of chitinases. This study contributes to an improved understanding of extraction of haze-forming PR proteins and phenolics that can influence bentonite requirement for protein stabilization.

Strip loins from different grades of cattle were subjected to two levels of high pressure processing (HPP) within 1h of slaughter at a commercial meat processing plant and chilled for 1day before freezing. The physical and eating quality characteristics of longissimus thoracis (strip loin) steaks from HPP were compared to meat that was chill aged for 1 or 28days. HPP produced meat after 1day with 60% lower shear force and higher sensory eating quality scores than 1day chill aged meat. Extended chill storage for 28days produced steaks of similar tenderness to HPP meat. HPP also increased the ultimate pH and decreased the cooking loss. Chilled storage of the gluteus medius from prime cattle for 28days significantly improved the shear force by 18%, whilst HPP improved both the shear force by 43% and the sensory eating quality scores. HPP can produce high eating quality eye of rump medallions within 1day of slaughter.

Deer milk is a liquid food with a very high nutrition and energy content. The milk from reindeer and moose has a long history of human consumption, and the growth of red deer farming has the potential for development of a dairy industry. Deer milk has the highest total fat, protein, and casein protein content of all the animal species whose milk has been used for human nutrition. Deer milk is also a very rich source of nutritional minerals, and the calcium, phosphorus, and zinc content is much higher than that found in cow, sheep, and goat milk. Changes in milk composition over the lactation period are similar to those found in other ruminants. The high-protein content in deer milk compared to other sources of milk offers unique potential for generating higher amounts of protein hydrolysate upon digestion and an interesting high-buffering capacity that may have potential medicinal benefits. Several anecdotal reports suggest potential health effects for deer milk and their fermented products, but scientific evidence to support this is still under investigation.

Background and Aims Protein instability has long been a technical issue in white wine production. The aims of this study were: to examine the variability of wine proteins from a single cultivar within a defined wine region over two vintages; and to investigate the correlation of the content of the total and individual proteins and protein haze with the bentonite dosage required for heat stability. Methods and Results Proteins in Sauvignon Blanc juices and wines from five selected Marlborough, New Zealand, vineyards with two pruning/training regimes (two- and four-cane vertical shoot positioned) were studied over two consecutive vintages. Proteins were quantified and characterised by Coomassie Brilliant Blue assay, sodium dodecyl sulfate polyacrylamide gel electrophoresis and sodium dodecyl sulfate capillary gel electrophoresis (SDS-CGE). The bentonite requirement for wine protein stability was determined by bentonite fining coupled with a hot/cold test. One vineyard consistently showed the lowest protein concentration and bentonite requirement regardless of pruning treatment and vintage, whereas others varied with pruning treatment and/or vineyard site and/or vintage. Two prevalent juice protein peaks at 22 and 28 kDa in SDS-CGE corresponded to two main wine protein peaks at 22 and 26 kDa, respectively. The 26 kDa fraction was reduced and became heterogeneous after fermentation, while the 22 kDa fraction remained unaffected. There was a good correlation between bentonite requirement and the 26 kDa fraction (R2 = 0.78). Conclusion The depletion of 26 kDa fraction in wine determined by SDS-CGE was a good indicator for protein stability by bentonite fining. Significance of the Study These results suggest that the method of protein quantification may have a strong influence on the utility of protein concentration measurement to predict the bentonite requirement of wine.

Trypsin inhibitor activity (TIA) of 17 spring-sown field pea cultivars grown in New Zealand ranged from 0.33 to 0.75 TIU/mg DM. These values were much lower than those reported for most European pea cultivars. After soaking and cooking, values fell by 42-91%, with an average reduction of 78% (0.07-0.19 TIU/mg DM). After heat treatment, the residual percentage of TIA was negatively correlated to the amount of TIA in the raw seed. Six to ten trypsin isoinhibitors were observed in each cultivar of the raw extracts, with isoelectric points ranging from 4.6 to 7.6. Only three of the isoinhibitors, with isoelectric points of 5.1, 5.9 and 7.6, remained after heat treatment. Pea cultivars with high TIA levels in the raw seed may be more suitable as processing peas because cooking substantially reduces TIA levels, suggesting that adverse effects of consuming TIA would be limited. Conversely, raw peas with low TIA levels would be more suitable for use as animal feed. Cultivars that contain more unstable isoforms may require less heat treatment, therefore retaining their nutritional value be more suitable for human consumption and use as animal feed, and have reduced processing costs.

Hydrothermal treatment (heating in water) is a common method of general food processing and preparation. For red-meat-based foods, boiling is common; however, how the molecular level effects of this treatment correlate to the overall food properties is not yet well-understood. The effects of differing boiling times on lamb meat and the resultant cooking water were here examined through proteomic evaluation. The longer boiling time was found to result in increased protein aggregation involving particularly proteins such as glyceraldehyde-3-phosphate dehydrogenase, as well as truncation in proteins such as in α-actinin-2. Heat-induced protein backbone cleavage was observed adjacent to aspartic acid and asparagine residues. Side-chain modifications of amino acid residues resulting from the heating, including oxidation of phenylalanine and formation of carboxyethyllysine, were characterized in the cooked samples. Actin and myoglobin bands from the cooked meat per se remained visible on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, even after significant cooking time. These proteins were also found to be the major source of observed heat-induced modifications. This study provides new insights into molecular-level modifications occurring in lamb meat proteins during boiling and a protein chemistry basis for better understanding the effect of this common treatment on the nutritional and functional properties of red-meat-based foods.

Thaumatin-like proteins (TLPs) and chitinases are the main constituents of so-called protein hazes which can form in finished white wine and which is a great concern of winemakers. These soluble pathogenesis-related (PR) proteins are extracted from grape berries. However, their distribution in different grape tissues is not well documented. In this study, proteins were first separately extracted from the skin, pulp and seed of Sauvignon Blanc grapes, followed by trypsin digestion and analysis by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Proteins identified included 75 proteins from Sauvignon Blanc grape skin, 63 from grape pulp and 35 from grape seed, mostly functionally classified as associated with metabolism and energy. Some were present exclusively in specific grape tissues; for example, proteins involved in photosynthesis were only detected in grape skin and proteins found in alcoholic fermentation were only detected in grape pulp. Moreover, proteins identified in grape seed were less diverse than those identified in grape skin and pulp. TLPs and chitinases were identified in both Sauvignon Blanc grape skin and pulp, but not in the seed. To relatively quantify the PR proteins, the protein extracts of grape tissues were seperated by HPLC first and then analysed by SDS-PAGE. The results showed that the protein fractions eluted at 9.3 min and 19.2 min under the chromatographic conditions of this study confirmed that these corresponded to TLPs and chitinases seperately. Thus, the relative quantification of TLPs and chitinases in protein extracts was carried out by comparing the area of corresponding peaks against the area of a thamautin standard. The results presented in this study clearly demonstrated the distribution of haze-forming PR proteins in grape berries, and the relative quantification of TLPs and chitinases could be applied in fast tracking of changes in PR proteins during grape growth and determination of PR proteins in berries at harvest.

Modern processing techniques for turkey involve rapid chilling to slow microbial growth and early deboning of the economically important breast meat. This paper shows that these 2 processes lead to significantly tougher meat with higher cooking losses. The toughening appears to be due to less extensive proteolysis and shortening of the sarcomeres. Calpains I and II and their inhibitor, calpastatin, were quantified in turkey breast. Calpain II was the more common isoform but showed no evidence of activation during aging. In contrast, calpain I and calpastatin activities declined rapidly and were no longer detected 24 h postslaughter. There was no evidence of an association between calpain activity and processing conditions.

Nitrogen assimilation was studied in the deciduous, perennial climber Clematis vitalba. When solely supplied with NO3– in a hydroponic system, growth and N-assimilation characteristics were similar to those reported for a range of other species. When solely supplied with NH4+, however, nitrate reductase (NR) activity dramatically increased in shoot tissue, and particularly leaf tissue, to up to three times the maximum level achieved in NO3– supplied plants. NO3– was not detected in plant material that had been solely supplied with NH4+, there was no NO3– contamination of the hydroponic system, and the NH4+-induced activity did not occur in tobacco or barley grown under similar conditions. Western Blot analysis revealed that the induction of NR activity, either by NO3– or NH4+, was matched by NR and nitrite reductase protein synthesis, but this was not the case for the ammonium assimilation enzyme glutamine synthetase. Exposure of leaf disks to N revealed that NO3– assimilation was induced in leaves directly by NO3– and NH4+ but not glutamine. Our results suggest that the NH4+-induced potential for NO3– assimilation occurs when externally sourced NH4+ is assimilated in the absence of any NO3– assimilation. These data show that the potential for nitrate assimilation in C. vitalba is induced by a nitrogenous compound in the absence of its substrate and suggest that NO3– assimilation in C. vitalba may have a significant role beyond the supply of reduced N for growth.

Effects of chilling (5 °C) period, light and applied nitrogen (N) on germination (%), rate of germination (d to 50% of total germination; T 50% ) and seed imbibition were examined in Clematis vitalba L. In the absence of chilling, light and N, germination was minimal (3%). When applied alone, both chilling and N increased germination. Chilling for 12 weeks increased germination to 64%, and 2.5 m M NO − 3 or NH + 4 increased germination to 10–12%. Light did not increase germination when applied alone, but did when applied in combination with chilling and/or N. Half the seed germinated when light was combined with 2.5 m M NO − 3 or NH + 4 . The influence of chilling, light and/or N on germination was greater when combined, than when either factor was applied alone. Both oxidized (NO − 3 ) and reduced (NH + 4 ) forms of N increased germination, but non-N-containing compounds did not, suggesting the response was due to N and not ionic or osmotic effects. Without additional N, T 50% decreased from 16–20 d at zero chilling, to around 5 d at 8 and 12 weeks chilling. Although T 50% was not influenced by an increase in NO − 3 or NH + 4 from 0.5 to 5.0 m M , it did increase with additional applied N thereafter. However, the magnitude of the N effect was small compared to that of chilling. Like germination, seed imbibition increased with a longer chilling period, but in contrast imbibition decreased slightly with increased applied NO − 3 or NH + 4 . It is argued that increased imbibition is not directly related to an increase in total germination, but that it may be related to the rate of germination. Possible mechanisms involved in the reduction in dormancy of C. vitalba seed are discussed.

Chlorsulfuron (15 g a.i. ha -1 ) inhibited growth of wheat (Triticum aestivum L. cv. Rongotea) especially on high nitrate (NO 3 - ) supply. Decreased growth at high NO 3 - was associated with higher concentrations of reduced nitrogen (N) and NO 3 - in the shoots. Seven days after spraying (DAS), shoot dry weight (dry wt) of sprayed plants was similar with NO 3 - or branched chain amino acids as main N supply but 28 DAS, shoot dry wt was greater with the amino acid treatment. One DAS, chlorsulfuron caused substantial decreases in extension of the youngest leaf and acetolactate synthase activity and valine content of shoots of plants supplied with NO 3 - or branched chain amino acids. Total amino acid content of shoots was greater in sprayed plants than in unsprayed plants 1 DAS. Acetolactate synthase activity of sprayed plants supplied low NO 3 - returned to normal 14-21 DAS. For sprayed plants transferred from low to high NO 3 - supply 7, 14 or 21 DAS, shoot dry wt 50 DAS increased with increased time of transfer to high NO 3 - while shoot NO 3 - content decreased. Shoot NO 3 - content of sprayed plants transferred to high NO 3 - supply 7 or 14 DAS was similar to that in unsprayed plants at applied NO 3 - concentrations which inhibited growth. It is concluded that inhibition of acetolactate synthase is likely to be the primary mode of action of chlorsulfuron in this wheat cultivar ; data are consistent with the proposal that subsequent NO 3 - accumulation can also inhibit growth.

The ability of pre-rigor infusion of kiwifruit juice to improve the tenderness of lamb was investigated. Lamb carcasses were infused (10% body weight) with fresh kiwifruit juice (Ac), water (W) and a non-infusion control (C) treatment. Infusion treatment had no effect on lamb hot carcass weight, cold carcass weight and chilling evaporative losses. The infused treatment carcasses of Ac and W had lower (P

There is controversy about the effect of storage time on metmyoglobin (MetMb) reducing activity in the sarcoplasmic fraction of meat and the role of this reducing activity in maintaining the color of red meat. The presence of metmyoglobin reducing activity in the myofibrillar fraction of muscle extracts was investigated as a possible reason for this controversy. NADH-dependent MetMb reducing activity was found in the particulate fraction of meat following sedimentation of a meat homogenate at 35 000g. There was 5.8 times more MetMb reducing activity in the particulate fraction compared with that of the sarcoplasmic (supernatant) fraction. The presence of metmyoglobin reducing activity in the myofibrils (MMRA), defined as the activity in the sediment after centrifugation of a meat homogenate at 2 000g, was confirmed. The myofibrillar fraction contained 63% of the total MetMb reducing activity available in the meat. The relationship between muscle MetMb reducing activities and meat color parameters was investigated in a beef patties system. The particulate MetMb reducing activity (PMRA) in beef patties was found to be a good indicator of the total metmyoglobin reducing activity in meat and was positively correlated with the color parameters of the patties, suggesting that PMRA may be associated with red meat color of meat patties.

The effects of antioxidants on oxidative processes and metmyoglobin-reducing activity in beef patties were investigated in two experiments. In the first experiment colour, colour stability, TBA values and MetMb-reducing activity were measured during storage, at 2 °C, of raw beef patties treated with four antioxidants (resveratrol, carnosine, quercetin and rutin) at two concentrations (110 and 550 μmol/kg meat ). In the second experiment the method of application of resveratrol was tested further. The storage period and antioxidant treatment affected colour, colour stability and TBA values. The colour-stabilising effect of the antioxidants was in the following order resveratrol>quercetin>rutin>carnosine. The performance of resveratrol was affected by the method of application. Resveratrol gave the highest protective effect against lipid peroxidation. Carnosine acted as a pro-oxidant under the specified experimental conditions. MetMb-reducing activity remained relatively stable during storage. It was concluded that the lack of NADH and not the loss of MetMb enzymatic activity was the factor limiting the MetMb-reducing activity in beef patties and, consequently, the factor dictating the colour and colour stability of beef patties.

This study was conducted to determine whether electrical stimulation per se can be omitted when other electrical inputs to beef carcasses (stunning and immobilisation) are used. In addition, we investigated which sample preparation method at 1 day post mortem (p.m.), cooked fresh, frozen, or after thawing, had the best predictive value for shear force after ageing of the muscle. Beef carcasses were electrically immobilized (75 V, 15 Hz) before and during exsanguination for 20 or 80 s and meat quality characteristics of the longissimus were determined at 1 and 7 days post mortem. Muscles from carcasses receiving the higher electrical input were similar in tenderness at 1 day p.m., but tougher at 7 days p.m. This result could be explained by the effect of muscle shortening and post mortem proteolysis on tenderness. These results indicate that even low electrical input during immobilization can adequately stimulate carcasses and avoid cold shortening. Freezing samples resulted in a considerable improvement in tenderness and cooking samples from the frozen state had the highest predictive value for tenderness after ageing. In a second experiment it was determined that freezing and thawing did not result in appreciable differences in cooking loss or proteolysis. The tenderising effect of freezing may be explained by tissue damage due to ice formation.

Effects of nitrogen supply (N-supply) on the photosynthetic apparatus of Clematis vitalba L. grown at several irradiances were determined by measuring soluble protein content, rubisco activity, photosynthetic pigment content and composition, and the photochemical efficiency of photosystem II (Fv/Fm). Compared to low irradiance (3 and 10% full sunlight), leaves grown at higher irradiance (up to full sunlight) had up to 5–6 times the soluble protein content and rubisco activity, and up to 2–4 times the total carotenoid content, on both a leaf area and a chlorophyll basis. On a leaf area basis, decreased N-supply reduced soluble protein concentration, rubisco activity and total carotenoid concentration to a greater extent at high compared to low irradiance. On a chlorophyll basis, in contrast, soluble protein and rubisco activity decreased by over 40% with increased N-supply (1.0–0.1 mol m-3) at high irradiance but N-supply did not influence the concentration of total carotenoids. Leaves grown at high compared to low irradiance had a greater concentration of xanthophyll cycle pigments (V+A+Z), β-carotene and lutein (but not neoxanthin) on a chlorophyll basis, and a slightly lower Fv/Fm. Nitrogen- supply did not influence the composition of the photosynthetic pigment pool, Fv/Fm, or the extent of de-epoxidation of the V+A+Z pool. The results suggest that irradiance-acclimation of C. vitalba can occur regardless of N-supply. Under N limitation at high irradiance, a balance between light capture and photosynthetic capacity is important rather than an increase in xanthophyll cycle-dependent energy dissipation. The importance of lutein as a light-harvesting pigment is questioned. A rapid method for the reversed phase-HPLC separation of carotenoids is described.