Search

Extraction of cellulose and hemicellulose from natural resources has attracted considerable interest. In comparison to other cereals, there is relatively little knowledge on the cellulose, hemicellulose and lignin content of sorghum by-products. As such, the aims of this study were to develop a multi-step process for sorghum by-products (bran, stalk and panicles) fractionation and characterise them with regards to their physicochemical properties. In terms of chemical composition, sorghum panicles were found similar to bran, featuring a significant presence of arabinoxylans as well. A sequential alkaline extraction with varying concentrations of NaOH was applied, resulting in the generation of three fractions (residue, hemicellulose and alkali soluble lignin). Fractionation of sorghum stalks with 1.0 M NaOH at 50oC for 3 h obtained ~64% (w/w) cellulose rich fraction and 52 % (w/w) of xylose, predominant in the hemicellulose fraction. In the bran, the fractionation with 0.75 M NaOH at 50oC for 3 hours obtained ~40% (w/w) cellulose rich fraction. Approximately 76% of the glucose was in hemicellulose fraction reflecting starch solubilisation in the case of bran, while nearly 2% (w/w) alkaline-soluble lignin was extracted. Overall, this study demonstrated an effective approach for the fractionation and the recovery of key components in sorghum by-products

Bacterial cellulose (BC) has attracted much research interest, delivering a combination of exclusive properties, such as flexibility, hydrophilicity, crystallinity, and a three-dimensional network. In this study, the effects of carbon source and cultivation conditions on BC production by the bacterium Komagataeibacter xylinus subsp. sucrofermentans DSM 15973 were assessed. Fructose was the most suitable carbon source and high BC concentrations up to 31 g/L were achieved in substrates with 60 g/L fructose, under static culture conditions. Notably, BC production was equally high under the same fermentation conditions in agitated cultures (~30 g/L). Moreover, the effectiveness of NaOH and NaOCl solutions in BC purification, and their potential impact on BC structure and properties were explored. The combination of weak NaOH and sodium hypochlorite (NaOCl) was proved an effective purification method, preserving the fibre structure and crystallinity of BC.

The management of staggering volume of food waste generated (∼1.3 billion tons) is a serious challenge. The readily available untapped food waste can be promising feedstock for setting up biorefineries and one good example is bread waste (BW). The current review emphasis on capability of BW as feedstock for sustainable production of platform and commercially important chemicals. It describes the availability of BW (>100 million tons) to serve as a feedstock for sustainable biorefineries followed by examples of platform chemicals which have been produced using BW including ethanol, lactic acid, succinic acid and 2,3-butanediol through biological route. The BW-based production of these metabolites is compared against 1G and 2G (lignocellulosic biomass) feedstocks. The review also discusses logistic and supply chain challenges associated with use of BW as feedstock. Towards the end, it is concluded with a discussion on life cycle analysis of BW-based production and comparison with other feedstocks.

Background There is substantial demand for gut health products incorporating probiotics and prebiotics. They are being delivered as ingredients in an increasing range of different product formulations. While new delivery matrices are assessed for their potential impact on cell viability and prebiotic degradation, it is unknown whether they should be expected to independently alter the clinical effect of a given probiotic and prebiotic. Scope and Approach We provide an overview of preclinical and clinical data to examine the degree to which probiotic and prebiotic efficacy may be altered by processing and incorporation into various delivery matrices. We also consider the impact of inter-individual host factors on product efficacy. We further review regulatory positions across the globe on substantiation of prebiotic and probiotic efficacy in the final product format. Key Findings and Conclusions In vitro data suggest that the delivery matrix may interact with prebiotic and probiotic functions via various physicochemical interactions with molecular and cellular structures and changes in cellular expression. However, direct evidence to suggest these changes have a significant in vivo impact is very limited. Indeed, meta-analyses suggest an elasticity robustness of effect across delivery matrices. Regulatory expectations vary among regions, but scope typically exists for adequate scientific justification to translate probiotic or prebiotic evidence across product formats. Early evidence suggests host factors such as diet, health and microbiome status are likely to play an important role in an individual’s response to a given probiotic and prebiotic.

This study examined the effect of dehydration on the phenolic compounds and antioxidant activity of blackcurrant (Ribes nigrum L.) pomaces (DBP) subjected to hot air oven drying (HOD), industrial rotary drying (IRD) and freeze drying (FD). Temperature and residence time were evaluated for HOD, whereas air-on and air-off temperature, ratio of drum rotor speed to air speed and particle size were evaluated for IRD. The highest total anthocyanins (ATC) and flavonols (FLV) were obtained in particle size of > 5.0 mm using IRD at 475°C/97°C (air-on/air-off) and higher ratio of drum rotor speed to air speed. Smaller size particles were found susceptible to degradation due to high temperature and retention time applied in IRD, resulting in loss of phenolic compounds in DBP, thus HOD was deemed more suitable. Overall, drying method selection and parameters of operation are key in preserving the concentrations of individual HCA and FLV in DBP.

Purpose Studies on broccoli (Brassica oleracea var. italica) indicate beneficial effects against a range of chronic diseases, commonly attributed to their bioactive phytochemicals. Sulforaphane, the bioactive form of glucoraphanin, is formed by the action of the indigenous enzyme myrosinase. This study explored the role that digestion and cooking practices play in bioactivity and bioavailability, especially the rarely considered dose delivered to the colon. Methods The antimicrobial activity of sulforaphane extracts from raw, cooked broccoli and cooked broccoli plus mustard seeds (as a source myrosinase) was assessed. The persistence of broccoli phytochemicals in the upper gastrointestinal tract was analysed in the ileal fluid of 11 ileostomates fed, in a cross-over design, broccoli soup prepared with and without mustard seeds. Results The raw broccoli had no antimicrobial activity, except against Bacillus cereus, but cooked broccoli (with and without mustard seeds) showed considerable antimicrobial activity against various tested pathogens. The recovery of sulforaphane in ileal fluids post soup consumption was Escherichia coli K12, no inhibitory effects were observed. Analysis of glucosinolates composition in ileal fluids revealed noticeable inter-individual differences, with six “responding” participants showing increases in glucosinolates after broccoli soup consumption. Conclusions Sulforaphane-rich broccoli extracts caused potent antimicrobial effects in vitro, and the consumption of sulforaphane-enriched broccoli soup may inhibit bacterial growth in the stomach and upper small intestine, but not in the terminal ileum or the colon.

This study reports the development of a novel and simple formulation for probiotic delivery using chitosan-coated agar-gelatin gel particles. This methodology involves the production of agar-gelatin particles by thermally treating a mixture of agar and gelatin solutions at high temperatures (121 °C) and subsequently coating with chitosan. The particles were able to protect the probiotic strain Lactobacillus plantarum NCIMB 8826 during incubation for 2 h in simulated gastric fluid (pH 2), as no statistically significant loss (P > 0.05) in cell concentration was observed, and also resist dissolution in simulated intestinal fluid (pH 7.2). Interestingly, this protection is related to the fact that the intense thermal treatment affected the physicochemical properties of agars and resulted in the formation of a strong and tight polymer network, as indicated by the X-ray diffraction (XRD) analysis. Using an in vitro faecal batch fermentation model simulating the conditions of the distal part of the large intestine (pH 6.7–6.9), it was demonstrated by quantitative real-time PCR that the majority of L. plantarum cells were released from the agar-gelatin particles within 30 to 48 h. Overall, this work led to the development of a novel methodology for the production of probiotic-containing particles, which is simpler compared with current encapsulation technologies and has a lot of potential to be used for the controlled release of probiotics and potentially other solid bioactives in the large intestine.Key Points• Chitosan gel particles is a simple and scalable method of probiotic encapsulation.• Autoclaving agar-gelatin particles increases their stability at low pH.• Chitosan gel particles protected L. plantarum during gastrointestinal conditions.• Probiotics could be controlled release in the colon using chitosan gel particles.

Adhesion ability to the host is a classical selection criterion for potential probiotic bacteria that could result in a transient colonisation that would help to promote immunomodulatory effects, as well as stimulate gut barrier and metabolic functions. In addition, probiotic bacteria has a potential protective role against enteropathogens through different mechanisms including production of antimicrobial compounds, reduction of pathogenic bacterial adhesion and competition for host cell binding sites. The competitive exclusion by probiotic bacteria not only has a beneficial effect on the gut but also in the urogenital tract and oral cavity. On the other hand, prebiotics may also act as barriers to pathogens and toxins by preventing their adhesion to epithelial receptors.\ud In vitro studies with different intestinal cell lines has been widely used along the last decades to assess the adherence ability of probiotic bacteria and pathogen antagonism. However, extrapolation of these results to in vivo conditions still remain unclear, leading to the need of optimization of more complex in vitro approaches that includes interaction with the resident microbiota to address the current limitations. \ud The aim of this mini-review is to provide a comprehensive overview on the potential effect of the adhesive properties of probiotics and prebiotics on the host by focusing on the most recent findings related with adhesion and immunomodulatory and antipathogenic effect on human health.

The authors would like to acknowledge the Biotechnology and Biological Sciences Research Council (BBSRC) and Mars Wrigley Confectionery for their financial support on a collaborative Global Challenges Research Fund (GCRF) project entitled “Development of novel value chain from cocoa pod husks in Indonesia: Technological, environmental and socio-economic challenges of a value chain” (BB/P022995/1). The uptake of innovative technologies and practices in agriculture aimed at the valorisation of natural resources can be scant in Low and Middle Income Countries (LMICs). Integration of financial viability assessments with farmers and environmental evaluations can help to understand some aspects of the low uptakes of innovations. Using the case study of Cocoa Pod Husk (CPH) valorisation in Indonesia, we provide insights into (i) a choice modelling method to assess the economic viability of CPH valorisation and (ii) an agronomic trial assessing the consequences on soil quality of diverting CPH from its role as a natural fertilizer. The economic viability assessment suggested that farmers require higher levels of compensation than might be expected to collect or process CPH (a small proportion of farmers would undertake all processing activities for 117 GBP/t CPH). The agronomic trial concluded that CPH plays only a minor role in the maintenance of soil phosphorus, calcium and magnesium, but it plays an important role for crop potassium. CPH removal would reduce the partial balances for carbon and nitrogen by 15.6% and 19.6%, respectively. Diversion of CPH from current practices should consider the long-term effects on soil quality, especially because it might create increased reliance on mineral fertilizers. Publisher PDF

Currently, astaxanthin demand is fulfilled by chemical synthesis using petroleum-based feedstocks. As such, alternative pathways of natural astaxanthin production attracts much research interest. This study aimed at optimising bioreactor operation parameters for astaxanthin production and evaluating strategies for its subsequent extraction. The effect of pH and agitation was evident, as a significant reduction in both biomass and astaxanthin production was observed when the culture pH was not controlled and a low agitation speed was applied. At controlled pH conditions and a high agitation speed, a significant increase in biomass (16.4 g/L) and astaxanthin production (3.6 mg/L) was obtained. Enzymatic yeast cell lysis using two commercial enzymes (Accellerase 1500 and Glucanex) was optimised using the central composite design of experiment (DoE). Accellerase 1500 led to mild cell disruption and only 9% (w/w) astaxanthin extraction. However, Glucanex treatment resulted in complete astaxanthin extractability, compared to standard extraction method (DMSO/acetone). When supercritical CO2 was employed as an extraction solvent in Accellerase-pre-treated Xanthophyllomyces dendrorhous cells, astaxanthin extraction increased 2.5-fold. Overall, the study showed that extraction conditions can be tailored towards targeted pigments present in complex mixtures, such as in microbial cells.

The aim of this study was to investigate the effects of different solvent and extraction temperatures on the free and bound phenolic compounds and antioxidant activity of dried blackcurrant skins (DBS). Apart from acetic acid buffer solution, different solvent systems, including water, methanol, and mixtures of methanol/water, were also employed and the effects of solvent and temperature (30 and 50 °C) on the free and bound forms of anthocyanins, hydroxycinnamic acids, and flavonols yield were assessed. The results showed that among all solvents, acetic acid buffer resulted in the highest free anthocyanin content (1,712.3 ± 56.1 mg/100 g) (P 0.05) after 2 hr extraction at 50 °C from DBS, while lower amounts of bound anthocyanins and anthocyanidins were detected after acid hydrolysis. Acetic acid buffer extracts exhibited the highest free hydroxycinnamic acid content (268.0 ± 4.5 mg/100 g), total phenolic content (3702.2 ± 259.3 mg GAE/100 g), and DPPH activity (60.7 ± 2.0% of inhibition). However, their free flavonol content was slightly lower (60.2 ± 0.8 mg/100 g) compared to 100% methanol at 30 and 50 °C (71.4 ± 1.5 mg/100 g and 71.5 ± 6.2 mg/100 g, respectively). Two-way ANOVA indicated interactions between solvent and temperature (P 0.05), which suggested that the relationship between solvent and phenolic compounds depends on the extraction temperature. PRACTICAL APPLICATION: Overall, acetic acid buffer is more environmental friendly, efficient, and cost effective than other solvents, thus, offering an improved extraction method for phytochemicals as valuable ingredients for nutraceutical applications, from underutilized dried blackcurrant skins (DBS).

Purpose To test the prebiotic activity of wheat arabinogalactan-peptide (AGP), which is a soluble dietary fibre composed of arabinogalactan polysaccharide linked to a 15-residue peptide, which accounts for up to 0.4% of the dry weight of wheat flour. Methods The prebiotic activity of AGP prepared from white wheat flour was tested using in vitro fermentation by colonic bacteria in automated pH-controlled anaerobic stirred batch cultures and compared to fructooligosaccharide (FOS) and wheat flour arabinoxylan (AX). Bacterial populations were measured using fluorescence in situ hybridisation (flow-FISH) and short chain fatty acid (SCFA) concentrations were measured using HPLC. Results Fermentation of AGP resulted in a significant bifidogenic activity and increased concentrations of SCFAs, mainly acetate after 24 h of fermentation. Conclusions These results were comparable to those obtained with AX and confirm the prebiotic potential of AGP. Furthermore, fermentation of a mixture of AGP and AX was faster compared to the single substrates and more similar to FOS, indicating that combinations of fermentable carbohydrates with different structures are potentially more effective as prebiotics than single substrates. Electronic supplementary material The online version of this article (10.1007/s00394-019-01908-7) contains supplementary material, which is available to authorized users.

D-Lactic acid production is gaining increasing attention due to the thermostable properties of its polymer, poly-D-lactic acid (PDLA). In this study, Lactobacillus coryniformis subsp. torquens, was evaluated for its ability to produce D-lactic acid using Dried Distillers Grains with Solubles (DDGS) hydrolysate as the substrate. DDGS was first subjected to alkaline pretreatment with sodium hydroxide to remove the hemicellulose component and the generated carbohydrate-rich solids were then subjected to enzymatic hydrolysis using cellulase mixture Accellerase® 1500. When comparing separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) of L. coryniformis on DDGS hydrolysate, the later method demonstrated higher D-lactic acid production (27.9 g/l, 99.9% optical purity of D-lactic acid), with a higher glucose to D-lactic acid conversion yield (84.5%) compared to the former one (24.1 g/l, 99.9% optical purity of D-lactic acid). In addition, the effect of increasing the DDGS concentration in the fermentation system was investigated via a fed-batch SSF approach, where it was shown that the D-lactic acid production increased to 38.1 g/l and the conversion yield decreased to 70%. In conclusion, the SSF approach proved to be an efficient strategy for the production of D-lactic acid from DDGS as it reduced the overall processing time and yielded high D-lactic acid concentrations.

Supercritical fluid extraction (SFE) has been widely used for extracting several valuable phytochemicals, including carotenoids. However, there is a scarcity of works dealing with the purification of SFE extracts. The aim of this work was to assess the feasibility and efficiency of a hydrophobic interaction chromatography (HIC) protocol for purifying carotenoid-rich extracts obtained by SFE. Initial batch experiments were carried out to calculate the resin adsorption capacity and adsorption kinetics. Subsequent runs were performed in a manually-packed chromatographic column, using the Amberlite XAD-1180N resin, where breakthrough curves and adsorption isotherms were obtained and fitted to the Langmuir model. The antioxidant activity and carotenoid degradation rates were monitored throughout the processes. In batch, the resin presented a maximum carotenoid adsorption capacity of 1.89 μg/mg, while in column, this value increased to 10.4 μg/mg. The global carotenoid adsorption rate was 93.3% and the elution rate, 94.7%, resulting in a global recovery of 88.4% for total carotenoids and 92.1% for carotenes. The Langmuir model fitted well the experimental data. Analysis of the extracts demonstrated that a 5.5-fold reduction in extract mass was achieved, accompanied by a 4.7-fold and 2.1-fold increase in carotenoid concentration and antioxidant activity, respectively. This work presents a novel process based on preparative HIC for the purification of carotenoid extracts and provides a fundamental understanding on process performance. It is potentially scalable and can be implemented in extraction and purification of carotenoids from natural sources, as an alternative to their production through chemical synthesis.

An ammonium sulfate precipitation of\ud fermentation broth produced by Bacillus subtilis FBL-1\ud resulted in 2.9-fold increase of specific protease activity.\ud An eluted protein fraction from the column chromatographies\ud using DEAE-Cellulose and Sephadex G-75 had 94.2- and\ud 94.9-fold higher specific protease activity, respectively.\ud An SDS-PAGE revealed a band of purified protease at\ud approximately 37.6 kDa. Although purified protease showed\ud the highest activity at 45°C and pH 9.0, the activity remained stable in temperature range from 30 to 50°C and pH range from 7.0 to 9.0. Protease activity was activated by metal ions such as Ca2+, Mg2+, Mn2+, Fe2+, Ca2+ and K+, but\ud 10 mM Fe3+ significantly inhibited enzyme activity (53%).\ud Protease activity was inhibited by 2 mM EDTA as a\ud metalloprotease inhibitor, but it showed good stability\ud against surfactants and organic solvents. The preferred\ud substrates for protease activity were found to be casein\ud (100%) and soybean flour (71.6%).

The aim of this study was to microencapsulate Bifidobacterium longum subsp. infantis CCUG 52486 using the extrusion method in a variety of matrices, namely sodium alginate (SA), sodium alginate-cow milk (SACM), sodium alginate-goat milk (SAGM) and sodium alginate-casein hydrolysate (SACH), and to evaluate the survival of free and encapsulated bacterial cells under different conditions. The encapsulation yield, size and surface morphology of the microcapsules were evaluated. The survival of microencapsulated bacterial cells and free bacterial cells were evaluated under simulated gastrointestinal conditions as well as in refrigeration, cow milk, and goat milk during storage at 4 °C for 28 days. The average size of SACM capsules and SAGM capsules was 2.8 ± 0.3 mm and 3.1 ± 0.2 mm respectively. Goat milk and cow milk-based matrices resulted in dense microcapsules which led to better performances in simulated gastrointestinal conditions than SA and SACH microcapsules. The bacterial cells encapsulated in SAGM showed the highest survival rate in cow milk (7.61 log cfu g−1) and goat milk (8.10 log cfu g−1) after the storage of 28 days. The cells encapsulated in SA and SACH and the free cells performed poorly under the simulated gastrointestinal conditions and in all different storage conditions. This study showed that SACM and SAGM are suitable to encapsulate B. longum subsp. infantis CCUG 52486 using the extrusion technique and more specifically, SAGM has a potential to be used as a new encapsulation material for encapsulating probiotic bacteria, resulting in milk and goat milk-based products with higher probiotic cell concentrations during refrigerated storage.

This study investigated the effect of acidified water at different pH values and extraction time on the phenolic profile (anthocyanins, hydroxycinnamic acids and flavonols), antioxidant activity and colour characteristics of dried blackcurrant pomaces (DBP) extracts. Extractions were carried out using acetic acid in water (pH 1.5, 2.0, 2.5 and 3.0) for 2 and 6 h at 30 °C. Phenolics concentration in DBP extracts were influenced by the pH of acidified water (p

Soybean protein extraction was evaluated using conventional (alkaline phosphate buffer) and ultrasonication assisted methods. The impact of the extraction method on protein yield, chemical composition, and structural properties of the protein isolates was assessed. In conventional alkaline extraction, increasing pH values (from 9 to 12) led to an increase in the protein yield, with pH 12 favouring protein extraction, with yields up to 36 % (w/w). Ultrasonication process at the same pH, led to maximum protein extraction yield of 84 % (w/w). Secondary structural changes in ultrasonicated OPI samples were linked to cavitation effects and the duration of the extraction, rather than the intensity of ultrasonication process. Extracted proteins exhibited increased β-sheet content, improved zeta-potential and smaller particle size of ultrasonicated proteins, rendering them suitable ingredients for tailored food applications.

Highlights • AX was determined in wheat grain after commercial and laboratory alcohol production. • Samples from laboratory scale production were similar to those from commercial processing. • The concentration, solubility and dynamic viscosity of AX increased during processing. • AX in DDGS was less variable in composition and properties than that in whole grain. • DDGS has potential to provide a source of AX for novel products., Laboratory produced DDGS samples were compared with commercial samples from a distillery and a biofuel plant. Changes in structure, solubility and content of arabinoxylan (AX) was determined. The distillation process results in a relative increase of AX content compared to the starting material. The heating and drying processes involved in the production of DDGS lead to an increased solubility and viscosity of water-extractable AX. Production of DDGS results in structural changes to the AX. There is a decrease in 2- and 3-linked arabinose oligosaccharides, that contributes to around a 50% reduction in arabinosylation in DDGS compared with the starting grains. The current study shows that laboratory-scale DDGS provide an accurate representation of the commercial scale and that the AX composition of DDGS is consistently uniform irrespective of starting material. The uniformity of DDGS and thin stillage makes them a good potential source of AX for production of prebiotics or other novel products.

Levan, a bacterial exopolysaccharide (EPS), has been suggested to have several biological activities, such as antitumour\ud activity and lowering blood pressure. There has also been interest in its potential prebiotic activity. This\ud study investigated the fermentation profile of a levan fraction from Erwinia sp. 10119 (average DP=137)\ud throughout a three-stage continuous gut model system, in which inulin HP (average DP=40) was included as a\ud comparison. Levan-type fructan was found to selectively stimulate the growth of Bifidobacterium and Eubacterium\ud rectale - Clostridium coccoides group in all fermenter vessels, with significant (p < 0.05) increases in the concentration\ud of both acetate and butyrate. The increases in Bifidobacterium population were significantly\ud (p < 0.05) higher in the models treated with levan-type fructan (0.8–1.24 log cell/mL) compared to the models\ud treated with inulin HP (0.62–0.7 log cell/mL), indicating a stronger bifidogenic effect of levan-type fructan and a\ud prolonged persistence in the colon due to its higher DP.

We optimized culture conditions using Bacillus sp. FBL-2 as a poly-(&gamma, glutamic acid) (PGA) producing strain isolated from cheonggukjang. All experiments were performed under aerobic conditions using a laboratory scale 2.5 L fermentor. We investigated the effects of fermentation parameters (temperature, pH, agitation, and aeration) and medium components (glutamic acid, citric acid, and yeast extract) on poly-(&gamma, glutamic acid) production, viscosity, and dry cell mass. A non-optimized fermentation method (1.5 vvm, 350 rpm, and 37 &deg, C) yielded PGA, viscosity, and dry cell mass at levels of 100.7 g/L, 483.2 cP, and 3.4 g/L, respectively. L-glutamic acid, citric acid, and yeast extract supplementation enhanced poly-(&gamma, glutamic acid) production to 175.9 g/L. Additionally, the production of poly-(&gamma, glutamic acid) from rice bran and wheat bran was assessed using response surface methodology (central composite rotatable design). Agricultural byproducts (rice bran and wheat bran) and H2SO4 were selected as factors, and experiments were performed by combining various component concentrations to determine optimal component concentrations. Our experimentally-derived optimal parameters included 38.6 g/L of rice bran, 0.42% of H2SO4, 28.0 g/L of wheat bran, and 0.32% of H2SO4. Under optimum conditions, rice bran medium facilitated poly-(&gamma, glutamic acid) production of up to 22.64 g/L, and the use of wheat bran medium yielded up to 14.6 g/L. Based on a validity test using the optimized culture conditions, poly-(&gamma, glutamic acid) was produced at 47.6 g/L and 36.4 g/L from these respective mediums, and both results were higher than statistically predicted. This study suggests that rice bran can be used as a potential alternative substrate for poly-(&gamma, glutamic acid) production.

Agricultural by-products comprise abundant, renewable sources of value-added compounds for the food and packaging industries. The production of biodegradable foams can be focused on replacement of polystyrene-foam with biodegradable materials, which are regarded as environmentally friendly. In this study, biodegradable food trays were developed via thermopressing, using modified and unmodified corn starches with additional extracted fractions (celluloses, hemicelluloses, and lignin) from sorghum stalk and bran. The effect of several formulations of extracted fractions from sorghum by-products on bio-foam properties was studied. All trays presented thicknesses between 3 and 4.17 mm, density between 0.16 and 0.64 g cm−3, and moisture content between 5 and 12% (dry basis). The foam trays made from chemically modified starch had lower densities, higher tensile strength and elongation at break than unmodified starch. The increment of cellulose fraction from 2% to 5% and hemicellulose fraction from 1% to 10% had significant effect on the trays’ physical and mechanical properties. All trays exhibited no color and structural changes during storage at 25 °C and 4 °C. The formulation presenting the best properties contained 2% of cellulose and 1% of hemicellulose, had a maximal resistance of 0.77 MPa and 9.46 mJ of total work, attributes which corresponded to a compact, homogenous, and dense microstructure.

Besides viability protection, a sufficiently prolonged gastrointestinal retention of probiotics has emerged as critically important in improving the functional effectiveness of gastrointestinal delivery of these microorganisms. In this work, we formulated pure, resistant starch-reinforced and chitosan-coated alginate microparticles using an electrospray technique and evaluated their performance as mucoadhesive probiotic formulations for gastrointestinal delivery. In addition, we designed and successfully validated a novel experimental set-up of in vitro wash-off mucoadhesion test, using a portable and low-cost USB microscope for fluorescence imaging. In our test, pure chitosan microparticles (positive control) exhibited the greatest mucoadhesive property, whereas the alginate-resistant starch ones (negative control) were the least retentive on a gastric mucosa. These electrosprayed formulations were spherically shaped, with a size range of 30–600 µm (60–1300 µm with chitosan coating). Moreover, model probiotic Lactobacillus plantarum loaded in alginate-starch formulations was better protected against simulated gastric conditions than in alginate ones, but not better than in the chitosan-coated ones.

The aim of this work was to evaluate a previously-developed model on supercritical fluid extraction (SFE) for carotenoid recovery from carrot peels on various carotenoid-rich fruit and vegetable wastes. To this end, 15 matrices, including flesh and peels of sweet potato, tomato, apricot, pumpkin and peach, as well as flesh and wastes of green, yellow and red peppers, were submitted to SFE under optimised conditions (59 °C, 350 bar, 15 g/min CO2, 15.5% (v/v) ethanol as co-solvent, 30 min of extraction time). The obtained extracts were characterised for their total carotenoid content, antioxidant activity and total carotenoid recovery (TCR). TCR values were greater than 90% w/w for most samples, with β-carotene being the most successfully extracted compound (TCRs 88⁻100% w/w). More polar carotenoids, such as lutein and lycopene, exhibited lower TCRs. A comparison with literature data suggested that carotenoid extraction is partially dependent on the composition of vegetable matrices, specifically on polysaccharide and moisture content. The results indicated that the optimised SFE conditions can be used as a general model for carotenoid extraction from various fruit and vegetable matrices and as a viable method for adding value to these waste streams by generating carotenoid-rich extracts.

Cocoa pod husk (CPH) is the main by-product (ca. 70–75% weight of whole fruit) of the cocoa harvest, an important and economic crop in developing countries. It is a rich source of minerals (particularly potassium), fibre (including lignin, cellulose, hemicellulose and pectin) and antioxidants (e.g. phenolic acids). An existing practise is the return of CPH to soil with potential benefits (or disadvantages) for cocoa productivity and soil sustainability that have not been fully characterised. Currently, alternative low-value applications of CPH include its use as animal feed, as a starting material for soap making and activated carbon. Other biotechnological valorisation potentials for CPH and its fractions include the production of bio-fuels and their incorporation in food systems. Physical, chemical or biological pre-treatment approaches are needed in order to achieve desirable fractions in a cost-effective and sustainable manner for novel applications in food and non-food sectors.

Polymer films were developed utilising proteins extracted from wheat distillers’ dried grains with solubles (DDGS) and in-process samples (wet solids), both by-products of bioethanol production process. Structural characterisation of DDGS and wet solids films indicated a change in the secondary structure of the proteins, reflecting the impact of DDGS production process such as effect of enzyme on protein properties and consequently on the film properties; whereas the developed films exhibited a rough surface with voids. Determination of moisture sensitivity indicated that DDGS films exhibited more hydrophilicity than wet solids films, with the same trend being observed for their water solubility and water uptake. The moisture content and solubility of DDGS films ranged from 10.2–14.2% and 32.3–41.8% respectively whereas those for wet solids’ film ranged from 18.9–19.8% and 23.8–24.2% respectively. The mechanical properties of DDGS and wet solids (ranging from 0.27–0.32 MPa) were comparatively lower than commercial wheat gluten film (0.6 MPa). The poor mechanical properties and high water vapour permeability of DDGS and the wet solids films limit their application as biodegradable packaging materials. However, based on their hydrophilicity, the developed films have potential applications in agriculture and horticulture as controlled release matrices and soil conditioners.

Distillers’ dried grains with solubles (DDGS) is a low-value agro-industrial by-product, rich in arabinoxylans (AX), which is produced by commercial distillery and bioethanol plants. In a first approach, we investigated the prebiotic potential of four fractions comprising arabinoxylan oligosaccharides (AXOS) and xylooligosaccharides (XOS) obtained by enzymatic hydrolysis of AX fractions derived from DDGS and wet solids (in-process sample of DDGS production process). Anaerobic batch cultures in controlled pH conditions were used to test the prebiotic activity of the samples. Results did not show significant differences between the enzymatic treatments used, and all AXOS/XOS were extensively fermented after 24 h. In addition, significant increases (P

This work aimed to assess and optimise the extraction of carotenoids from carrot peels by supercritical CO2 (S-CO2), utilising ethanol as co-solvent. The evaluated variables were temperature, pressure and co-solvent concentration. According to the validated model, the optimal conditions for maximum mass yield (5.31%, d.b.) were found at 58.5 °C, 306 bar and 14.3% of ethanol, and at 59.0 °C, 349 bar and 15.5% ethanol for carotenoid recovery (86.1%). Kinetic experiments showed that 97% of the total extractable carotenoid content was recovered after only 30 min, whereas model fitting confirmed the fast extraction trend and desorbing nature of carotenoids from the sample matrix. The process is potentially scalable, as demonstrated by runs performed with a 10-fold initial sample size, which led to even higher recoveries (96.2%), indicating that S-CO2 can be as efficient as a conventional solvent extraction for recovering high value compounds from vegetable by-products.

Pre-treatment of stationary phase cells of Lactobacillus plantarum NCMIB 8826 with citric acid (pH 3 to 6) for a short period of time significantly improved subsequent cell survival in several highly acidic fruit juices namely cranberry (pH 2.7), pomegranate (pH 3.5), and lemon & lime juices (pH 2.8). Although the mechanism for this adaptation is still unclear, the analysis of the cellular fatty acid content of acid adapted cells and the reverse transcription polymerase chain reaction (RT-PCR) showed a significant increase (by ~1.7 fold) of the cellular cyclopropane fatty acid, cis-11,12-methylene octadecanoic acid (C19:0cyclow7c) and a significant upregulation (~12 fold) of cyclopropane synthase (cfa) were observed, respectively, during acid adaptation. It is likely that these changes led to a decrease in membrane fluidity and to lower membrane permeability, which prevents the cells from proton influx during storage in these low pH fruit juices.

This study investigated the stability of freeze dried and fluid bed dried alginate microcapsules coated with chitosan containing model probiotic bacteria, Lactobacillus plantarum, during storage for up to 45days at different water activities (0.11, 0.23, 0.40 and 0.70) and temperatures (4, 30 and 37°C). The loss in cell viability was around 0.8 log in the case of fluid bed drying and around 1.3 in the case of freeze drying, with the former method resulting in dried capsules of smaller size (~1mm vs 1.3mm), more irregular shape, and with a rougher surface. In both cases, the water activity and water content were less than 0.25 and 10% w/w, respectively, which favours high storage stability. The storage stability studies demonstrated that as the water activity and temperature decreased the survival of the dried encapsulated cells increased. Considerably better survival was observed for fluid bed dried encapsulated cells compared to freeze dried encapsulated cells and freeze dried free cells with 10% sucrose (control), and in some cases, e.g. at 4 and 30°C at water activities of 0.11, 0.23 and 0.40, there was more than 1 log difference after 45days, with concentrations higher than 108CFU/g after 45days of storage. The results indicate that fluid bed drying is an effective and efficient manufacturing method to produce probiotic containing capsules with enhanced storage stability.

Prebiotics are dietary carbohydrates that favourably modulate the gut microbiota. The aims of the present study were to develop a functional prebiotic bread using Bimuno®, (galactooligosaccharide (B-GOS) mixture), for modulation of the gut microbiota in vitro in individuals at risk of metabolic syndrome. A control bread, (no added prebiotic) and positive control bread (containing equivalent carbohydrate to B-GOS bread) were also developed. A 3-stage continuous in vitro colonic model was used to assess prebiotic functionality of the breads. Bacteria were quantified by fluorescence in situ hybridization and short chain fatty acids by gas chromatography. Ion-exchange chromatography was used to determine GOS concentration after bread production. Following B-GOS bread fermentation numbers of bifidobacteria and lactobacilli were significantly higher compared to controls. There was no significant degradation of B-GOS during bread manufacture, indicating GOS withstood the manufacturing process. Furthermore, based on previous research, increased bifidobacteria and butyrate levels could be of benefit to those with obesity related conditions. Our findings support utilization of prebiotic enriched bread for improving gastrointestinal health.