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Assessing the authenticity of PDO cheeses is an important task because it allows consumer expectations to be fulfilled and guarantees fair competition for manufacturers. A 3-year survey was carried out, analyzing 271 samples of grated Grana Padano (GP) PDO cheese collected on the European market. Previously developed analytical methods based on proteomics approaches were adopted to evaluate the compliance of market samples with selected legal requirements provided by the specification for this cheese. Proteolysis follows highly repeatable pathways in GP cheese due to the usage of raw milk, natural whey starter, and consistent manufacturing and ripening conditions. From selected casein breakdown products, it is possible to calculate the actual cheese age (should be >9 months) and detect the presence of excess rind (should be <18%). Furthermore, due to the characteristic pattern of free amino acids established for GP, distinguishing it from closely related cheese varieties is feasible. Cheese age ranged from 9 to 25 months and was correctly claimed on the label. Based on the amino acid pattern, three samples probably contained defective cheese and there was only one imitation cheese. Few samples (9%) were proven to contain some excess rind. Overall, this survey highlighted that the adopted control parameters can assure the quality of grated GP. [ABSTRACT FROM AUTHOR]

The present study investigated some physico-chemical and microbiological traits of 20-month ripened hard cheeses produced from low-temperature high-speed centrifuged raw milk that developed a structural defect consisting of eyes or slits in the paste. Cheeses obtained using the same process and that did not develop the defect were used as controls. The colour, texture, moisture, water activity, proton molecular mobility, microstructure, extent of proteolysis, and viable microorganisms have been evaluated in all the cheese samples, and the significant differences between the defective and non-defective cheeses have been critically discussed. At a microstructural level, the defects caused fat coalescence and an unevenly organised protein matrix with small cracks in the proximity of the openings. The different fat organisation was correlated to a different transverse relaxation time of 1H population relaxing at higher times. The textural and colour features were not different from those of the control cheeses and were comparable with those reported in the literature for other long-ripened hard cheeses. On the other hand, the defective cheeses showed a higher moisture level and lower lactobacilli and total mesophilic bacteria concentrations, but the microbial origin of the defect remains an open hypothesis that deserves further investigation. [ABSTRACT FROM AUTHOR]

Biopolymers of different natures (carbohydrates, proteins, etc.) recovered from by-products of industrial processes are increasingly being studied to obtain biomaterials as alternatives to conventional plastics, thus contributing to the implementation of a circular economy. The food industry generates huge amounts of by-products and waste, including unsold food products that reach the end of their shelf life and are no longer usable in the food chain. Milk proteins can be easily separated from dairy waste and adapted into effective bio-based polymeric materials. Firstly, this review describes the relevant properties of milk proteins and the approaches to modifying them for subsequent use. Then, we provide an overview of recent studies on the development of films and coatings based on milk proteins and, where available, their applications in food packaging. Comparisons among published studies were made based on the formulation as well as production conditions and technologies. The role of different additives and modifiers tested for the performances of films and coatings, such as water vapor permeability, tensile strength, and elongation at break, were reviewed. This review also outlines the limitations of milk-protein-based materials, such as moisture sensitivity and brittleness. Overall, milk proteins hold great potential as a sustainable alternative to petroleum-based polymers. However, their use in food packaging materials at an industrial level remains problematic. [ABSTRACT FROM AUTHOR]

Heat–stable peptidase AprX, released by Pseudomonas species in raw milk during cold storage, can cause gelation of UHT milk since it is able to split caseinomacropeptides (CMPtot) from κ-casein, so inducing aggregation of casein micelles. Identifying raw milk susceptibility to gelation would allow UHT milk manufacturers to select appropriate processing conditions or give the milk a different destination. Two approaches, i.e., detection of free CMPtot and evidence of casein aggregates, were evaluated as possible indicators for early detecting milk destabilization. With this aim, microfiltered milk was inoculated with a P. fluorescence strain and incubated at either 4 or 25 °C. The presence of CMPtot was detected using capillary electrophoresis after 96 and 24 h at the two temperatures, respectively, when milk also became heat unstable and small flocks of protein appeared. Confocal laser scanning microscopy evidenced initial aggregates of casein micelles after 48 and 24 h at 4 and 25 °C, respectively. Keeping the milk at 25 °C/24 h could be a useful condition to accelerate milk destabilization. Despite the similar timing of instability detection, presence of CMPtot was the only trait specific for AprX activity. [ABSTRACT FROM AUTHOR]

With the aim of developing bioprocesses for waste valorization and a reduced water footprint, we optimized a two-step fermentation process that employs the oleaginous yeast Cutaneotrichosporon oleaginosus for the production of oil from liquid cheese whey permeate. For the first step, the addition of urea as a cost-effective nitrogen source allowed an increase in yeast biomass production. In the second step, a syrup from candied fruit processing, another food waste supplied as carbon feeding, triggered lipid accumulation. Consequently, yeast lipids were produced at a final concentration and productivity of 38 g/L and 0.57 g/L/h respectively, which are among the highest reported values. Through this strategy, based on the valorization of liquid food wastes (WP and mango syrup) and by recovering not only nutritional compounds but also the water necessary for yeast growth and lipid production, we addressed one of the main goals of the circular economy. In addition, we set up an accurate and fast-flow cytometer method to quantify the lipid content, avoiding the extraction step and the use of solvents. This can represent an analytical improvement to screening lipids in different yeast strains and to monitoring the process at the single-cell level. [ABSTRACT FROM AUTHOR]

Increasing awareness of balanced diet benefits is boosting the demand for high-protein food and beverages. Sports supplements are often preferred over traditional protein sources to meet the appropriate dietary intake since they are widely available on the market as stable ready-to-eat products. However, the protein components may vary depending on both sources and processing conditions. The protein fraction of five commercial sports supplements was characterized and compared with that of typical industrial ingredients, i.e., whey protein concentrates and isolates and whey powder. The capillary electrophoresis profiles and the amino acid patterns indicated that, in some cases, the protein was extensively glycosylated and the supplemented amino acids did not correspond to those declared on the label by manufacturers. The evaluation by confocal laser scanning microscopy evidenced the presence of large aggregates mainly enforced by covalent crosslinks. The obtained findings suggest that, beside composition figures, provisions regarding sports supplements should also consider quality aspects, and mandatory batch testing of these products would provide more reliable information to sport dieticians. [ABSTRACT FROM AUTHOR]

Coconut husk, rubberwood sawdust, and palm leaf base are cellulosic agricultural wastes that have potential to be processed to fiber as absorbing material. This study investigated characteristics (morphological, physiological properties, chemical composition, absorption capacity, and water absorption isotherms) of coconut, rubberwood, and palm fiber. Also, the study aimed to develop an antimicrobial sachet packaging to resist against foodborne pathogens (Listeria monocytogenes, Staphylococcus aureus, Salmonella spp., and Escherichia coli) by adding lime oil (LO) emulsion or Litsea cubeba (LC) oil at 50 to 700 µL into the material (1 g) before, and then dried and placed in the 1-L seal box. Results showed that among the three, coconut performed the best in terms of releasing the essential oil (EO) emulsion against bacteria. Coconut could adsorb and release volatile LO or LC at the lowest concentrations (LO, 500 µL/L; LC, 300 µL/L) to inhibit bacteria compared with the other fibers (700 µL/L) at 35 °C. Results indicated that coconut has a low water absorption rate, which influenced the faster adsorption of EO emulsion in the beginning of the process; therefore, using low concentrations of EO in coconut for bacterial inhibition is possible. Coconut contains 34.5% lignin, 68.7% holocellulose, 37.6% cellulose, and 31.2% hemicellulose. Coconut is suitable as an alternative to the biocomposite material in developing a new antimicrobial packaging design. [ABSTRACT FROM AUTHOR]

BACKGROUND Pre‐harvest sprouting of wheat is viewed negatively because of the high level of enzymatic activity, which leads to a deterioration in the bread‐making performance of the related flours. On the other hand, improvements in bread properties (i.e. volume and crumb softness) are reported when sprouted wheat under controlled conditions is used in mixtures with a conventional unsprouted flour. However, knowledge about the effects of sprouting on gluten functionality and its relationship with bread features is still limited, especially in the case of whole wheat flour. RESULTS: Under the conditions applied in this study (48 h, 20 °C and 90% relative humidity), proteins of sprouted wheat were still able to aggregate, even if changes in gluten aggregation kinetics suggested gluten weakening. On the other hand, sprouting led to an increase in gluten stretching ability, suggesting an increase in dough extensibility. In the dough system, sprouting was responsible for a decrease in water absorption, development time, and stability during mixing. However, when the values for development time and water absorption indicated by the Farinograph® were followed carefully, sprouting improved bread height (~20%), specific volume (~15%), and crumb softness (~200% after 24 h of storage), even when whole wheat flour was used. CONCLUSION: It is possible to produce bread with improved volume and crumb softness using whole wheat flour from sprouted kernels. Thus, sprouting can be exploited as a pre‐treatment to improve the bread‐making performance of fiber‐enriched systems. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

• Specific bacterial proteolysis of k-casein may cause gelation of UHT milk. • Caseinomacropeptides can be early indicators of gelation onset in UHT milk. • Capillary electrophoresis allows caseinomacropeptides to be determined. • Cold storage of raw milk increases susceptibility of the derived UHT milk to gelation. Heat-stable peptidases released in refrigerated raw milk by psychrotrophic bacteria are responsible for UHT milk gelation. K-casein-derived caseinomacropeptides, identified by mass spectrometry, were constantly detected in gelled milk by capillary electrophoresis. Strains of Pseudomonas fluorescens , Ps. poae and Chryseobacterium joostei, selected among aprX -positive strains from raw milk, were incubated in milk up to 6 days at 4 °C before sterilization (98 °C/4 min). Samples were then stored at 25 or 40 °C, visually observed for gelation, and analysed for presence of caseinomacropeptides throughout 90 days of storage. Depending on cold pre-incubation time, caseinomacropeptides accumulated well before gelation onset in milk stored at 25 °C. Caseinomacropeptides were successively degraded, especially in milk stored at 40 °C, due to extensive proteolysis, and an abundant sediment developed instead of a gel. The caseinomacropeptides are here presented as an early indicator of UHT milk gelation and a mechanism explaining this phenomenon is proposed. [ABSTRACT FROM AUTHOR]

The late blowing defect still represents a problem for hard cheeses. Thus, the behaviour of the cheese spoiling bacterium C. tyrobutyricum was studied throughout the cheesemaking and ripening of Grana Padano using an innovative approach. Cells and spores, independently sealed within dialysis tubes, were kept in the vat during the entire cheesemaking and then into cheese until 6-month ripening. At each sampling step, morphological changes of cells and spores were monitored by electron microscopy and supported with plate counts. Vegetative cells died during curd cooking and then were no longer cultivable. However, 2 × 10 2 spores appeared at the end of this stage, likely triggered by the exponential growth phase, and were present until 6-month ripening. In cheese, C. tyrobutyricum UC7086 proved to convert free arginine to citrulline and then to ornithine, and to produce γ-aminobutyric acid by glutamate transamination rather than by decarboxylation. Compartmentalization of vegetative cells and spores into dialysis tubes was effective in studying their respective behaviour in a real cheesemaking. This approach allowed to demonstrate that the number of vegetative cells in milk in addition to that of spores should be considered for the eradication of the late blowing defect. [ABSTRACT FROM AUTHOR]

Inadequate intake of vitamin D is a global health issue related to severe diseases, mainly involving subjects with dark skin pigmentation, patients affected by malnutrition, malabsorption syndromes, or obesity, and elderly people. Some foods fortified with vitamin D have been tested in vivo, but fortification strategies with a global outreach are still lacking. This review is focused on food fortification with vitamin D, with the aim to collect information on (a) formulation strategies; (b) stability during processing and storage; and (c) in vitro bioaccessibility. Approaches to add vitamin D to various foods were analyzed, including the use of free vitamin D, vitamin D loaded in simple and double nanoemulsions, liposomes, casein micelles, and protein nanocapsules. Numerous studies were reviewed to elucidate the impact of food technologies on vitamin D's stability, and mechanisms that lead to degradation were identified—namely, acid-catalyzed isomerization, radical-induced oxidation, and photo-oxidation. There is, however, a lack of kinetic data that allow for the prediction of vitamin D's stability under industrial processing conditions. The roles that lipids, proteins, fibers, and antioxidants play in vitamin bioaccessibility have been clarified in various studies, while future needs include the design of specific food matrices that simultaneously achieve a balance between the long-term stability, bioaccessibility and, ultimately, in vivo functionality of vitamin D. [ABSTRACT FROM AUTHOR]

Vitamin D is essential in assuring bone health at all stages of life, but its non-skeletal effects are also essential: This vitamin impacts the physiology of the immune system, skeletal muscles and adipose tissue, glucose metabolism, skin, cardiovascular and reproductive systems, neuro-cognitive functions and cell division. The incidence of vitamin D deficiency is widespread worldwide, at any age, in young and healthy subjects, as well as in pregnant women and the elderly population, due to several factors, including inadequate sunlight exposure, skin pigmentation and coverage, adiposity, lifestyle and low dietary intakes. To overcome this problem, the fortification of foods that are consumed on a daily basis, such as milk, is strongly advisable. This opinion paper aims to discuss, in a multidisciplinary way, the current evidence supporting the importance of vitamin D in health and disease and the role of milk as an optimal carrier of this vitamin, to promote adequate intakes, highlighting its unique physico-chemical characteristics linked to both fat globule membrane and casein micelle structure. Moreover, it addresses the impact of industrial processing and storage of consumption milk on the stability of these structures, thus in determining vitamin D bioavailability and the achievement of adequate intakes. [ABSTRACT FROM AUTHOR]

Drinking milk with longer shelf-life is nowadays required to have access to markets of distant countries. Novel technologies for milk processing, alternative to conventional heat-treatments, may provide milk industry with reliable, efficient and clean equipment for drinking milk manufacture. This review addresses the most promising of these technologies, either under experimental examination or already commercially available. In particular, scientific literature documenting the performances of ohmic heating, microwaves, radio frequency, microfiltration, high pressure, pulsed electric field, and ultrasounds is presented. Attention is given to the respective effectiveness in destroying microorganisms, inactivating enzymes, and avoiding damage to milk components, as well as to the consequent microbiological and physicochemical stability of the processed milk during storage. Although most technologies allow to destroy or remove vegetative bacterial cells, so far none proves to represent a comprehensive alternative to conventional heat treatments. The combination of an alternative technology with mild thermal treatments represents, at the moment, the sole realistic approach to produce fresh-like/high quality pasteurized milk. • Sustainable milk processing technologies are needed for forthcoming food industry. • Non-thermal processing technologies still fail in ensuring milk safety. • Combination of novel technologies with mild heat treatment is a successful approach. [ABSTRACT FROM AUTHOR]

The implementation of quality assurance schemes for the assessment of PDO food authenticity is an issue involving manufacturers, traders, retailers and consumers. In this respect, reliable analytical methods are needed to integrate paper-trailing information. The feasibility of distinguishing the Italian Fontina PDO cheese from the generic Fontal cheese was preliminarily evaluated on a set of commercial samples by measuring selected parameters (pH, alkaline phosphatase activity, content of copper, volatiles, extent of proteolysis) related to the different manufacturing processes. The relative profile of free amino acids proved to be a promising tool. A new set of 41 samples of Fontina PDO cheese was collected at representative dairies within the recognized production area and analyzed for free amino acids. A chemometric model of Fontina PDO cheese was built based on the mean content and standard deviation of 15 free amino acids. On this basis, all of the PDO samples were correctly identified, whereas all of the Fontal cheeses were recognized as different cheeses. [ABSTRACT FROM AUTHOR]

The edible mushroom Agrocybe aegerita produces a ribotoxin-like protein known as Ageritin. In this work, the gene encoding Ageritin was characterized by sequence analysis. It contains several typical features of fungal genes such as three short introns (60, 55 and 69 bp) located at the 5′ region of the coding sequence and typical splice junctions. This sequence codes for a precursor of 156 amino acids (~17-kDa) containing an additional N-terminal peptide of 21 amino acid residues, absent in the purified toxin (135 amino acid residues; ~15-kDa). The presence of 17-kDa and 15-kDa forms was investigated by Western blot in specific parts of fruiting body and in mycelia of A. aegerita. Data show that the 15-kDa Ageritin is the only form retrieved in the fruiting body and the principal form in mycelium. The immunolocalization by confocal laser scanning microscopy and transmission electron microscopy proves that Ageritin has vacuolar localization in hyphae. Coupling these data with a bioinformatics approach, we suggest that the N-terminal peptide of Ageritin (not found in the purified toxin) is a new signal peptide in fungi involved in intracellular routing from endoplasmic reticulum to vacuole, necessary for self-defense of A. aegerita ribosomes from Ageritin toxicity. [ABSTRACT FROM AUTHOR]

Pseudomonas fluorescens spoiling raw milk produces a heat-stable protease, namely AprX, that may degrade k-casein with a chymosin-like activity thus causing gelation of commercial milk during storage. Four strains of P. fluorescens were selected for both the presence of aprX gene and proteolytic activity in milk agar plate (a negative control was included) and were incubated in various milk substrates, i.e. pasteurized milk, UHT milk and reconstituted milk powder, differing for heat-treatment and presence of fat, in order to evaluate whether the type of milk substrates could affect their growth and proteolytic activity. While bacterial growth was mainly influenced by temperature (4 or 25 °C) for all strains, HPLC and CZE patterns of incubated milk samples showed that the extent and trend of proteolysis were highly heterogeneous and not exclusively strain-dependent. Indeed, pasteurized milk was the only substrate where aprX -positive strains led to gelation onset whereas other milk types underwent different destabilization. Ultrastructural features observed by transmission electron microscopy for casein micelles, whey proteins and fat globules, where present, explained how the processing conditions, sometimes including repeated heat-treatments, may have influenced the extent of proteolysis operated by P. fluorescens strains in the tested milk substrates. This study has highlighted that different milk substrates may bring to different conclusions when used in experiments aiming to elucidate the mechanisms of bacterial proteolysis since both ultrastructural and compositional properties may impact on accessibility of cleavage sites to proteases. • Bacterial proteolysis in milk agar plates may differ from that in fluid milk. • Presence of fat influences proteolytic activity of Pseudomonas fluorescens in milk. • Pasteurized milk was the only substrate where proteolysis led to gelation onset. • Skim milk powder is not a suitable substrate for evaluating microbial proteolysis. [ABSTRACT FROM AUTHOR]

This research investigated the effect of sprouting on wheat bran. Bran from un-sprouted (BUW) and sprouted (BSW) wheat were characterized in terms of chemical composition, enzymatic activities, and hydration properties. In addition, the rheological properties (using GlutoPeak, Farinograph, Extensograph, and Rheofermentometer tests) and bread-making performance (color, texture, volume of bread) of wheat doughs enriched in bran at 20% replacement level were assessed. Sprouting process caused a significant decrease in phytic acid (~20%), insoluble dietary fiber (~11%), and water holding capacity (~8%), whereas simple sugars (~133%) and enzymatic activities significantly increased after processing. As regards the gluten aggregation kinetics, the BSW-blend profile was more similar to wheat than BUW-blend, indicating changes in the fiber and gluten interactions. BSW led to a worsening of the mixing and leavening properties, instead, no significant changes in extensibility were observed. Finally, BSW improved bread volume (~10%) and crumb softness (~52%). Exploiting bran from sprouted wheat might be useful to produce bread rich in fiber with enhanced characteristics. [ABSTRACT FROM AUTHOR]

Extending ripening of hard cheeses well beyond the traditional ripening period is becoming increasingly popular, although little is known about the actual evolution of their characteristics. The present work aimed at investigating selected traits of Parmigiano Reggiano cheese ripened for 12, 18, 24, 30, 40 and 50 months. Two cheeses per each ripening period were sampled. Although moisture constantly decreased and was close to 25% in 50-month cheeses, with a parallel increase in cheese hardness, several biochemical changes occurred involving the activity of both native and microbial enzymes. Capillary electrophoresis demonstrated degradation of αs1- and β-casein, indicating residual activity of both chymosin and plasmin. Similarly, continuous release of free amino acids supported the activity of peptidases deriving from lysed bacterial cells. Volatile flavor compounds, such as short-chain fatty acids and some derived ketones, alcohols and esters, evaluated by gas chromatography with solid-phase micro-extraction, accumulated as well. Cheese microstructure was characterized by free fat trapped in irregularly shaped areas within a protein network, with native fat globules being no longer visible. This study showed for the first time that numerous biochemical and structural variations still occur in a hard cheese at up to 50 months of aging, proving that the ripening extension deserves to be highlighted to the consumer and may justify a premium price. [ABSTRACT FROM AUTHOR]

Centrifugation is occasionally applied to clean cheese milk, particularly to remove Clostridia's spores that may cause the "late blowing" of cheese. The sludge separated by centrifugation also contains fat and protein, thus is sterilized and added back to cheese milk. In manufacture of raw milk cheeses, centrifugation shall be performed at temperature below 40 °C and no sterilized sludge can be added to vat milk. Both these limitations negatively affect cheese yield. To evaluate process sustainability, three different centrifugation configurations were tested at a factory producing a traditional raw-milk extra-hard cheese. Either a single or double centrifugation, the latter with two different volumes of discharged sludge, were tested over 3-week periods each. Efficiency of spore removal, decrease of total bacterial count, loss of milk solids and cheese yield were evaluated daily with respect to not-centrifuged milk from the same batch. Double centrifugation with low-volume sludge gave highest efficiency of spore removal, i.e. 98.2%, while the single process minimized the loss of cheese yield. Impedometric analysis indicated that centrifugation caused a preferential removal of rod-shaped lactic acid bacteria, regardless of configuration. This finding was confirmed by microscopy and suggested that a different bacteria population would operate during cheese ripening. • Double centrifugation of raw milk shows satisfactory spore removal. • Centrifugation sludge volume influences milk spore removal and protein loss. • Low-temperature milk centrifugation principally removes rod-shaped bacteria. [ABSTRACT FROM AUTHOR]

Bacterial production of exopolysaccharides (EPS) is of increasing interest near food manufacturers, biotechnology industries and nutritionists because of their different roles. Several analytical methods are available for recovery, quantification and characterization of EPS from lactic acid bacteria (LAB) in food. However, direct screening method for production of EPS is still based on the visual observation of filamentous texture of the colonies developed on supplemented solid growth media. To overcome weaknesses of many currently used screening methods, we propose adopting impedance microbiology to evaluate the EPS production from LAB in milk. In this work we have proven that the peculiar shape of capacitance curve of Lactobacillus delbrueckii subsp. bulgaricus 2214, measured in milk by means of a BacTrac 4300® system, is due to production of EPS. Besides the pH measurement, the amounts of EPS evaluated after 0, 8, 13 and 55 h of incubation in milk, were in agreement with the evaluation of gene expression and confirmed by the observations by confocal laser scanning microscopy and by transmission electron microscopy. With the aim to verify the applicability of the proposed method, the drop entity of the capacitance curve (ΔE%) of 22 EPS-producing (EPS+) LAB strains and one negative (EPS-) control was evaluated both in broth medium and in milk. The positive ΔE% value found for all of the strains cultivated in the clear broth medium allowed to confirm the EPS production, simply observing a strain-dependent amount of EPS on surface of the measurement electrodes of the device. When the same EPS+ strains were cultivated in milk, the obtained ΔE% values showed that only a few of them were able to produce EPS in this environment, supporting their diversified ability to utilize lactose for this purpose. Results obtained by this multidisciplinary study demonstrate that impedance microbiology represents a suitable method to overcome the limits of the most commonly used methods to screen LAB for EPS production in milk. Moreover, these results also open a door to the application to other food and beverages, in which the EPS produced in situ could be of great interest for food industry. • We hypothesized descending shape of conductance curve was due to EPS production. • Multidisciplinary study was used to prove our hypothesis. • The positive value of ΔE% is a measure of LAB EPS production. • This method could overcome the lacks of the common used screening methods in food. [ABSTRACT FROM AUTHOR]

The behaviour of soluble nitrogen compounds during Grana Padano cheese-making was studied at eight dairies. Raw milk, skimmed milk, sweet whey and the derived natural whey culture, collected from 24 processes, were analysed for soluble whey proteins (α-lactalbumin and β-lactoglobulin), proteose-peptones (PP), small peptides (SP), caseinomacropeptides (CMPs), and free amino acids (FAAs). The PP fraction increased during milk natural creaming, then part of it was selectively retained in the curd and the rest degraded in the first few hours of whey fermentation, together with α-lactalbumin, CMPs and part of SP. Features outlined for the whey culture were confirmed on 30 samples collected at six different dairies. A time course study of the whey fermentation showed that degradation of α-lactalbumin began when the pH dropped below 4, whereas β-lactoglobulin content did not change. Uptake of specific FAAs was shown to support the initial growth of lactic acid bacteria in whey. [ABSTRACT FROM AUTHOR]

• Effects of lighting on pasteurized milk in clear PET bottles were studied during shelf storage. • Major light-induced changes involved flavins, volatiles and sensory properties. • Shelf life of pasteurized milk was defined considering its overall characteristics. • Estimated shelf life was longer than that assigned by the manufacturer. • Light exposure management by retailers is crucial to preserve bottled milk quality. The stability of whole pasteurized milk packaged in clear PET bottles was studied throughout 13-days storage in the dark, but including, at specific times, light exposure of 6, 12 or 18 h to simulate conditions potentially occurring in refrigerated display counters. The aim was to investigate the effects of light exposure when overlapping the unavoidable endogenous modifications in pasteurized milk during storage. Dissolved oxygen, riboflavin and other flavins, proteolysis products, volatile compounds, and sensory characteristics were evaluated. Besides the expected progress of proteolysis occurring during storage, light negatively affected milk flavour especially after longer exposure times. The development of "mushroom" flavor related to the increase of volatile 2,3 octanedione was the most characterizing modification. Gathered data were considered in view of providing the background knowledge for the control of light exposure conditions on a retail display, thus supporting the shelf life extension of pasteurized milk in a fully recyclable packaging. [ABSTRACT FROM AUTHOR]