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Six commercial wine yeast strains and three nonindustrial strains of Saccharomyces cerevisiae were overexpressed with the GPD1 gene. The gene encodes a glycerol-3-phosphate dehydrogenase and its overexpression resulted in a 1.5 to 2.5 increase in glycerol level but a slight decrease in ethanol formation. The strains have higher amounts of succinate and acetate which vary between the commercial and nonindustrial strains. The concentration of acetoin and 2,3-butanediol were also found to be greater.

f. remize, y. augagneur, m. guilloux-benatier and j. guzzo. 2004.The aim of the study was to characterize the effect of various nitrogen sources onOenococcus oenigrowth, carbon source utilization, extracellular protease activity and extracellular proteins. More generally, the goal is to understand how nitrogen-based additives might act to enhance malolactic fermentation in wine.Five yeast extracts were used. As the amino acid and nitrogen analyses revealed, they were similar in global amino acid composition, except for arginine level. Nevertheless the ratio of amino acids between free/bound, and low/high molecular weight fractions were highly different. One of the yeast extracts led to a significant protease activity in the supernatant and to a poor final biomass of the IOB84·13 strain compared to the other ones. For the IOB84·13 strain specifically, arginine addition to the arginine poor yeast extract did not restore growth.35S-methionine-labelled extracellular proteins were separated by SDS-PAGE. Signals were detected in all media early in the growth phase and were maintained during 48 h of culture.A significant protease activity was detected forO. oenisupernatants during growth under nitrogen limitation but only for certain nitrogen sources. Moreover, the activity was strain dependent. Peptides (0·5–10 kDa) seemed to be more favourable for growth of wine bacteria than<0·5 kDa nitrogen sources. The extracellular protein signal patterns differed more greatly between the bacterial strains tested than between the nitrogen molecules in the medium.This is the first study extensively considering the role of the nitrogen source composition and level uponO. oenigrowth and metabolism. [ABSTRACT FROM AUTHOR]

Objectives: This study provides an overview of the composition of the raw root flesh of a panel of 22 sweet potato ( Ipomoea batatas L.) cultivars, with a focus on bioactive compounds. The large diversity of the proximate and phytochemical compositions observed between cultivars and within and between different flesh colors pointed out the importance of composition analysis and not only color choice for the design of foods with nutritional benefits., Methods: The nutritional composition (starch, protein, total dietary fibers) and bioactive compound composition of 22 cultivars from Reunion Island, maintained in the Vatel Biological Resource Center, were investigated., Results: Orange and purple cultivars stood out from white and yellow cultivars for their higher nutritional composition. Purple sweet potatoes were notable for their high contents of anthocyanins (55.7 to 143.4 mg/g dry weight (DW)) and phenolic compounds, in particular chlorogenic acid and ferulic acid, contributing to antioxidant activities, as well as their fiber content (14.1 ± 2.1% DW). Orange cultivars were rich in β-carotene (47.2 ± 0.7 mg/100 g DW) and to a lesser extent α-carotene (4.8 ± 1.2 mg/100 g DW). In contrast, certain white cultivars demonstrated suboptimal nutritional properties, rendering them less relevant even for applications where the lack of coloration in food is desired., Conclusions: Those characteristics enable the selection of sweet potato varieties to design food products ensuring optimal nutritional benefits and culinary versatility.

Scope: Lactic acid fermentation (LAF) modulates the composition of food, leading to changes in safety, sensory, and nutritional properties. The effects of lactic fermented pineapple juice (FJ) supplementation on energetic metabolism of high-fat diet (HFD) fed mice are compared with either water (control), sweetened water (SW), bacteria in SW, and pineapple juice (J) supplementation., Methods and Results: Drink consumption and body weight are measured during the 6 weeks of experiment, whereas glycemia and lipid content are determined at the beginning and at the end of the experiment. Total energy intake is similar between all groups though the volume of juice consumed is lower than that of SWs. Weight gain is higher for mice provided with sugary drinks (5.65 ± 1.32 to 7.74 ± 2.98 g) compared to water (4.68 ± 0.93 g). The FJ is less detrimental to blood carbohydrate regulation than other sugary drinks. Triglyceride (TG) and total cholesterol content are not modified following fermented juice or water consumption, contrarily to other sugary drinks. Whatever the drink, intestinal permeability is preserved. Lactic acid bacterium (LAB) population in feces is not affected by the beverage but species composition is modified., Conclusion: From a health perspective, FJ is preferable to other sugary drinks to limit metabolic disorders related to HFD., (© 2023 Wiley-VCH GmbH.)

This study investigated the effects of Lactiplantibacillus plantarum 75 (LAB 75) fermentation at 37 °C for 48 h on the pH, total soluble solids (TSS), colour, total titratable acidity (TTA), carotenoids, and bioactivities of cowpea leaf smoothies from three cultivars (VOP 1, VOP 3, and VOP 4). Fermentation reduced the pH from 6.57 to 5.05 after 48 h. The TTA increased with the fermentation period, whilst the TSS reduced. Fermentation of the smoothies resulted in the least colour changes (∆E) in VOP 1 after 48 h. Fermentation of cowpea smoothies (VOP 1, VOP 3, and VOP 4) improved the antioxidant capacity (FRAP, DPPH, and ABTS), which was attributed to the increase in total phenolic compounds and carotenoid constituents in all of the fermented cowpea smoothies. VOP 1 was further selected for analysis due to its high phenolic content and antioxidant activity. The VOP 1 smoothie fermented for 24 h showed the lowest reduction in TPC (11%) and had the highest antioxidant (FRAP, DPPH, and ABTS) activity. Ltp. plantarum 75 was viable and survived the harsh conditions of the gastrointestinal tract, and, hence, could be used as a probiotic. VOP 1 intestinal digesta showed significantly higher glucose uptake relative to the undigested and the gastric digesta, while the gastric phase had higher levels of α-amylase and α-glucosidase compared to the undigested samples.

Processing, such as fresh cutting and drying, is essential to enhance profitability; therefore, to limit waste and reduce losses in fruit production such as mangoes. Metabarcoding and microbial enumeration methods were utilized to explore the structure of mango microbiota, as well as their evolution after processing. Two mango ripening stages of cv. Cogshall were selected and processed into fresh-cut pieces or dried slices. Microbiological and physicochemical parameters were monitored during product storage, in order to assess the dynamics of quantitative and qualitative variations of the microbial flora. Proteobacteria was the dominant bacterial phylum of the mango surface and accounted for 73.16%, followed by Actinobacteria (10.16%), Bacteroidetes (7.82%) and Firmicutes (6.68%). Aureobasidium and Cladosporium were the only two genera shared between all types of samples (peel surface, dried slices and mango fresh-cut). However, the bacterial genera Lactobacillus and Pantoea were the most abundant in fresh-cut mango after 14 days of storage. Ascomycota was the dominant fungal phylum in the mango surface and accounted for 90.76% of the total number of detected sequences, followed by Basidiomycota (9.21%). In total, 866 microbial genera were associated with mango surface (562 bacterial and 304 fungal). Among detected yeast genera, Saccharomyces, Candida and Malassezia prevailed in mango flesh and were replaced by Wickerhamomyces after 14 days of storage. Alpha and beta diversity analyzes revealed differences in fungal and bacterial communities on fruit peel, in fresh-cut, dried slices, and during conservation (fresh-cut and dried slices). Mango processing (washing, peeling, cutting and drying) reduced the richness and the microbial diversity (bacterial and fungal) associated to the fruit, and drying limits the development of cultivable microorganisms during storage in comparison to fresh-cuts mangoes., Competing Interests: Declaration of competing interest The authors declare no known conflicts of interest associated with this publication and that there has been no significant financial support for this work that could have influenced its outcome., (Copyright © 2022. Published by Elsevier Ltd.)

The purpose of this study was to investigate the bioaccessibilities of total phenolic compounds, carotenoid profile, antioxidant activity, and Lactic acid bacteria (LAB) survival in fermented mango juice (MJs) obtained from three mango cultivars after exposure to an in vitro gastrointestinal digestion model. The MJs from three cultivars ('Sabre', 'Peach', and 'Tommy Atkins') were fermented using Lactiplantibacillus plantarum 75 (L75), Leuconostoc pseudomesenteroides 56 (L56), and their combination (L56 + 75). Fermented MJs were digested and fractions: gastric (GF), intestinal (IF), and dialysis (DF) were analyzed for total polyphenolic content (TPC), antioxidant activity (FRAP), 1-diphenyl-2-picrylhydrazyl (DPPH), and 2.2-azinobis-3-ethyl-benzothiazoline-6-sulfonic acid (ABTS). In addition, the carotenoid content and the LAB population were determined from the GF and IF. After digestion, TPC decreased while fermentation improved its bioaccessibility. L75 -fermented 'Sabre' MJs had the highest bioaccessible TPC in the GF (75.65%), IF (50.10%), and DF (32.52%) while L56 'Peach' MJs increased the β-carotene bioaccessibility by 1.32-fold at GF and IF (1.21-fold). When compared to the other two juices, 'Sabre' and 'Peach' MJs fermented with L75 showed the highest IC 50 values for DPPH and ABTS. Generally, L75-fermented 'Sabre' MJs had the highest LAB survival at both GF (7.57 Log CFU/mL) and IF (7.45 Log CFU/mL) and hold potential as probiotic juices. L56-fermented 'Sabre' MJs would ensure the delivery of four times the carotenoid recommended dietary allowance (RDA) to a target site in the body while L75-fermented 'Peach' MJs could be used to effectively counteract oxidants in the body system.

Increasing consumer demand for foods with high nutritional quality, prolonged shelf life and low environmental impact of the package, is driving innovation towards the development of new packaging. Multifunctional food packaging films, biodegradable, heat-sealable and antimicrobial, were developed. A PLA coating layer incorporating either sodium benzoate, potassium sorbate, or a combination of them was deposited onto a poly(lactic) acid/poly(butylene adipate-co-terephthalate) substrate film. The effectiveness of the developed systems to preserve the quality of foods was tested in shelf-life experiments performed on shredded carrots and pineapple juice, selected as model processed raw foods. The best performance was observed for the active film containing potassium sorbate: microbial populations increased less rapidly and were 0.7-1.8 log CFU/g lower at the end of storage period in this film than in control packs. Of the two model foods, the pineapple juice was better preserved: after 7 days in active packaging, color change and microbial counts of juice were below that of control, observed after one day and after 3 days of storage respectively. Moreover, the incorporation of the active phases did not significantly affect the mechanical, barrier and optical properties of the films, opening new ways to prolong shelf-life of minimally processed foods., Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05435-y., Competing Interests: Conflict of interestThe authors declare that they have no competing interests., (© Association of Food Scientists & Technologists (India) 2022.)

Biopolymeric systems that co-encapsulate probiotics and bioactive compounds ensure timely delivery in the gastrointestinal tract. Cyanidin 3-sambubioside is the dominant anthocyanin in Natal plum (Carissa macrocarpa). This study aims at the co-encapsulation of Natal plum (Carissa macrocarpa) juice inoculated with Lactiplantibacillus plantarum 75 (Ltp. plantarum 75) by freeze-drying using pea protein isolate, maltodextrin, and psyllium mucilage and evaluating their release in vitro. An encapsulation efficiency of >85% was noted in lactic acid bacteria (LAB) survival and anthocyanin content. Freeze-drying produced pinkish-red powder, rich in polyphenols and LAB (>6 Log CFU mL−1) after 14 days of storage. Natal plum juice + maltodextrin + pea protein isolate + psyllium mucilage + Ltp. plantarum 75 (NMPeaPsyB) showed the highest LAB population (6.74 Log CFU mL−1) with a survival rate of 81.9%. After digestion, NMPeaPsyB and NMPeaPsy had the highest LAB survival (>50%) at 67.5% and 67.5 ± 0.75%, respectively, and the highest bioaccessibility of cyanidin 3-sambubioside in Natal plum juice than the other co-encapsulation with other biopolymers. NMPeaPsy and NMPeaPsyB showed phenolic stability in the gastric phase and controlled release in the intestinal simulated phase. The antioxidant activities had strong correlations with cyanidin 3-sambubioside. The results confirmed that microencapsulation is important for improving stability and allowing for the development of functional foods.

The effects of lactic acid fermentation using Lactiplantibacillus plantarum 75 (L75), Leuconostoc pseudomesenteroides 56 (L56) and its combination (L56 + 75) on the quality, bioactive and volatile compounds of mango juices (MJ) from three cultivars (‘Peach’, ‘Sabre’ and ‘Tommy Atkins’) were investigated. Fermented and unfermented MJ were evaluated for LAB growth, physicochemical parameters, volatile compounds, antioxidants activities (DPPH, ABTS, FRAP methods), total phenolic content (TPC) and sensory properties. The unfermented juices served as a control. Twenty-four-hour fermentation was ideal for MJ based on LAB growth profiles. Generally, titratable acidity, TPC, FRAP, DPPH and ABTS scavenging activities significantly increased with fermentation by the L75 strain and were highest in the L75-fermented ‘Sabre’ MJ, while L75-fermented ‘Peach’ MJ had higher ABTS activity (p < 0.05). In contrast, the L56 strain enhanced β-carotene retention, with improved colour properties in L56-fermented ‘Peach’ MJ. Fermentation with L75 in ‘Sabre’ and ‘Peach’ MJ aided the synthesis of new volatile compounds (alcohols, esters, ketones and aldehydes). A PLS-DA scatter plot showed two clusters separating the ‘Peach’ and ‘Sabre’ mango juice fermented with L75 from the rest. Based on the variable importance of the projection value (VIP) scores, pentadecane, 8-hexyl and butyl isobutyrate were shown as marker candidates to distinguish ‘Peach’ and ‘Sabre’ MJ fermented with L75 from the other treatments, whereas ethyl octanoate and isobutyl acetate differentiated the ‘Sabre’ MJ fermented with L75 from the other treatments. ‘Sabre’ and ‘Peach’ MJ fermented with L75 and L56 could provide antioxidants, meeting the recommended daily requirements for ascorbic acid and carotenoids in adults and teenagers. Hence, lactic acid fermentation of these local cultivars is a way to benefit consumers.

Various homopolysaccharides (HoPSs) can be produced by bacteria: α- and β-glucans, β-fructans and α-galactans, which are polymers of glucose, fructose and galactose, respectively. The synthesis of these compounds is catalyzed by glycosyltransferases (glycansucrases), which are able to transfer the monosaccharides in a specific substrate to the medium, which results in the growth of polysaccharide chains. The range of HoPS sizes is very large, from 10 4 to 10 9 Da, and mostly depends on the carbon source in the medium and the catalyzing enzyme. However, factors such as nitrogen nutrients, pH, water activity, temperature and duration of bacterial culture also impact the size and yield of production. The sequence of the enzyme influences the structure of the HoPS, by modulating the type of linkage between monomers, both for the linear chain and for the ramifications. HoPSs' size and structure have an effect on rheological properties of some foods by their influence on viscosity index. As a consequence, the control of structural and environmental factors opens ways to guide the production of specific HoPS in foods by bacteria, either by in situ or ex situ production, but requires a better knowledge of HoPS production conditions.

This study describes the impact of utilising different strains of lactic acid bacteria (LAB) for the fermentation of papaya puree and their effect on the quality parameters and bioaccessibility of phenolic compounds during simulated in vitro gastrointestinal digestion. Papaya was processed into puree; pasteurised and fermented at 37 °C for 2 days; and stored for 7 days at 4 °C using LAB strains Lactiplantibacillus plantarum 75 ( L75*D2 ; L75*D7 ), Weissella cibaria 64 ( W64*D2 ; W64*D7 ) and Leuconostoc pseudomesenteroides 56 ( L56*D2 ; L56*D7 ), respectively. Non-fermented samples at 0 ( PPD0 ), 2 ( PPD2 ) and 7 days ( PPD7 ) served as controls. pH was reduced with fermentation and was lowest in L56*D2 (3.03) and L75*D2 (3.16) after storage. The colour change ( ΔE ) increased with the fermentation and storage of purees; L75*D7 showed the highest ΔE (13.8), and its sourness reduced with storage. The fermentation by W64*D7 and L75*D7 increased the % recovery of chlorogenic, vanillic, syringic, ellagic, ferulic acids, catechin, epicatechin and quercetin in the intestinal fraction compared to the L56*D7 and PPD7 . Fermentation by W64*D7 and L75*D7 significantly improved the antioxidant capacity of the dialysed fraction compared to the L56*D7 or PPD7 . L56*D7 -fermented papaya puree showed the highest inhibitory effect of α-glucosidase activity followed by L75*D7 . L75*D7 had a significantly higher survival rate. LAB fermentation affected the bioacessibilities of phenolics and was strain dependent. This study recommends the use of Lpb. plantarum 75 for fermenting papaya puree.

In this study, popularly consumed traditional chayote leaves and locally produced pineapple fruit were used to develop a fermented smoothie using lactic acid bacteria (LAB) strains: Lactobacillus plantarum ( L75 ), Weissella cibaria ( W64 ), and their combination ( LW64 + 75 ). The physicochemical parameters [pH, total soluble solids (TSS), and color], total phenols, and carotenoid contents of the smoothies fermented for 48 h and stored for 7 days at 4°C were compared with the unfermented (control) smoothies. Results indicated that LAB fermentation reduced the pH from 3.56 to 2.50 after 48 h (day 2) compared with the non-fermented smoothie at day 2 (pH 3.37). LAB strain L75 significantly reduced the TSS content of the smoothies to 13.06°Bx after 2 days of fermentation. Smoothies fermented by L75 showed overall acceptability after 7 days of storage compared with the non-fermented puree on day 0. The LW64 + 75 significantly reduced the color change (Δ E ), which was similar to the control. L75 increased the phenolic content, and W64 enhanced the total carotenoid content of the smoothies after 2 days of fermentation compared with other treatments. The use of an in vitro model simulating gastrointestinal (GI) digestion showed that fermentation with L75 improved the total phenol recovery by 65.96% during the intestinal phase compared with the control. The dialysis phase mimicked an epithelial barrier, and 53.58% of the recovered free soluble are bioavailable from the L75 fermented smoothies compared with the control. The antioxidant capacity of dialyzable fraction of the L75 fermented smoothie was significantly higher than that of the control and smoothies fermented with W64 or LW64 + 75 ., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Managa, Akinola, Remize, Garcia and Sivakumar.)

Underutilized or traditional leafy vegetables are grown in the wild and cultivated. They are consumed as nutritional accompaniments to staples, either raw (fresh), cooked, or in a dried form, through custom, habit, and tradition. These traditional leafy vegetables are natural rich sources of phytochemicals and nutritional compounds. Over time, the keenness for consumption of traditional vegetables has become less popular. Poor nutrient diets are the main cause of mortality and morbidity, especially in developing countries, where the problem is predominant due to poverty. Consumption of traditional vegetables can assist in the prevention of chronic disease development, as they contain various bioactive compounds that exhibit multiple health benefits. Traditional leafy vegetables play a vital role in combatting hunger, food insecurity, and malnutrition, and most are suitable for food intervention programs. African nightshade ( Solanum family) is one such commonly consumed traditional leafy vegetable. During dry seasons, communities often face shortages of vegetables; thus, the preservation of edible leaves is one strategy to help overcome this problem. The adoption of solar drying and fermentation are traditional methods to extend the availability of African nightshade vegetables. Additionally, the agronomy practices and postharvest processing methods affect the phytochemicals and nutritional compounds of African nightshade accessions. This mini-review provides information on changes in phytochemicals, nutrition, and antinutritive compounds with different postharvest processing methods and irrigation. The review provides the justification to promote the cultivation for consumption, by identifying the potential African nightshade accessions that are rich in phytonutritional compounds. This mini-review summarizes and discusses the major information on (i) the micro- and macronutrients present in Solanum retroflexum , the most commonly consumed nightshade species compared with other traditional vegetables in Southern Africa, (ii) the composition of phytochemical compounds present in different nightshade accessions, (iii) the impact of irrigation on phytochemical composition in different nightshade species, and (iv) the impact of postharvest processing on phytochemicals and antinutritive compounds in S. retroflexum . Inclusion of African nightshade, especially S. retroflexum , with the main staple foods can improve protein, iron, and calcium levels in daily diets, which will help to improve people's health and well-being., (Copyright © 2020 Sivakumar, Phan, Slabbert, Sultanbawa and Remize.)

This study aimed to investigate the influences of fermentation at 37 °C for 3 days by different lactic acid bacterium strains, Lactobacillus plantarum ( 17a ), Weissella cibaria ( 21 ), Leuconostoc pseudomesenteroides ( 56 ), W. cibaria ( 64 ) or L. plantarum ( 75 ), on color, pH, total soluble solids (TSS), phenolic compounds and antioxidant activity of African nightshade (leaves). Results indicated fermentation with L. plantarum 75 strain significantly decreased the pH and total soluble solids, and increased the concentration of ascorbic acid after 3 days. L. plantarum 75 strain limited the color modification in fermented nightshade leaves and increased the total polyphenol content and the antioxidant activity compared to the raw nightshade leaves. Overall, L. plantarum 75 enhanced the functional potential of nightshade leaves and improved the bioavailability of gallic, vanillic acid, coumaric, ferulic ellagic acids, flavonoids (catechin, quercetin and luteolin) and ascorbic acid compared to the other lactic acid bacterium strains. Correlation analysis indicated that vanillic acid and p -coumaric acid were responsible for the increased antioxidant activity. Proximate analysis of the fermented nightshade leaves showed reduced carbohydrate content and low calculated energy.

There are a several emerging and re-emerging RNA viruses that are prevalent around the world for which there are no licensed vaccines or antiviral drugs. Zika virus (ZIKV) is an example of an emerging virus that has become a significant concern worldwide because of its association with severe congenital malformations and neurological disorders in adults. Several polyphenol-rich extracts from plants were used as nutraceuticals which exhibit potent in vitro antiviral effects. Here, we demonstrated that the papaya pulp extracted from Carica papaya fruit inhibits the infection of ZIKV in human cells without loss of cell viability. At the non-cytotoxic concentrations, papaya pulp extract has the ability to reduce the virus progeny production in ZIKV-infected human cells by at least 4-log, regardless of viral strains tested. Time-of-drug-addition assays revealed that papaya pulp extract interfered with the attachment of viral particles to the host cells. With a view of preserving the properties of papaya pulp over time, lactic fermentation based on the use of bacterial strains Weissella cibaria 64, Lactobacillus plantarum 75 and Leuconostoc pseudomesenteroides 56 was performed and the resulting fermented papaya pulp samples were tested on ZIKV. We found that lactic fermentation of papaya pulp causes a moderate loss of antiviral activity against ZIKV in a bacterial strain-dependent manner. Whereas IC 50 of the papaya pulp extract was 0.3 mg/mL, we found that fermentation resulted in IC 50 up to 4 mg/mL. We can conclude that papaya pulp possesses antiviral activity against ZIKV and the fermentation process has a moderate effect on the antiviral effect.

Not much information is available on the changes of phenolic metabolites or anti-nutritive compounds in African nightshade leaves during moist cooking. Blanching methods (boiling, microwave, and steaming) using 5-20% lemon juice was compared with the plain water as a control. Lemon juice at 20% significantly increased the total colour differences (ΔE). Chlorophyll content and the overall acceptance were highest for samples steamed in 5% lemon juice. Steam blanching in plain water reduced the tannin, oxalate and phytate contents but showed higher comparative peak responses for steroidal saponins. Neochlorogenic, chlorogenic, and caffeoylmalic acid, kaempferol O-rhamnosyl hexoside, and rutin were identified blanched leaves. Principle component analysis (PCA) discriminated between blanching treatments while Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) showed clear group distinctions between the blanching treatments. Chlorogenic acid, neochlorogenic acid and cryptochlorogenic acid were the responsible biomarkers for the separation of the steam blanching treatments. Thus, steam blanching preserves the functional compounds in nightshade leaves., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Minimally-processed pineapple stored under refrigerated conditions is highly perishable. We aimed to characterize the evolution of physicochemical, sensory and microbiological quality during cold storage. Pineapple batches were sampled from several locations in Reunion Island and then minimally processed. In the processing step, the variability of firmness and counts of yeasts and molds were observed. Moreover, correlations between the sampling season and pH and b* color component, as well as between fungal population and b* parameter were observed. During storage, the visual aspect of pineapple cuts changed to brown and shiny, whereas olfactive descriptors shifted from fruity descriptors and fresh to fermented, alcoholic and milky. The values for pH, TA and TSS did not significantly vary according to storage time. A decrease in firmness and C* color parameter was observed. Yeast and mold counts were significantly higher after 7 days of storage. The diversity in yeasts and molds was mainly dependent on the considered batches observed from PCR-DGGE profiles. Fungal species were isolated from spoiled pineapple cuts. The implication of Penicilllium citrtrinum , Talaromyces amestolkiae , Rhodotorula mucilaginosa , Saccharomyces cerevisiae , and Meyerozyma caribbica in the spoilage of minimally-processed pineapple cuts was further demonstrated., Competing Interests: The authors declare no conflict of interest.

Fruit and vegetables are an important part of human diets and provide multiple health benefits. However, due to the short shelf-life of fresh and minimally-processed fruit and vegetables, significant losses occur throughout the food distribution chain. Shelf-life extension requires preserving both the quality and safety of food products. The quality of fruit and vegetables, either fresh or fresh-cut, depends on many factors and can be determined by analytical or sensory evaluation methods. Among the various technologies used to maintain the quality and increase shelf-life of fresh and minimally-processed fruit and vegetables, biological control is a promising approach. Biological control refers to postharvest control of pathogens using microbial cultures. With respect to application of biological control for increasing the shelf-life of food, the term biopreservation is favored, although the approach is identical. The methods for screening and development of biocontrol agents differ greatly according to their intended application, but the efficacy of all current approaches following scale-up to commercial conditions is recognized as insufficient. The combination of biological and physical methods to maintain quality has the potential to overcome the limitations of current approaches. This review compares biocontrol and biopreservation approaches, alone and in combination with physical methods. The recent increase in the use of meta-omics approaches and other innovative technologies, has led to the emergence of new strategies to increase the shelf-life of fruit and vegetables, which are also discussed herein.

Non-heading Chinese cabbage ( Brassica rapa L. subsp. chinensis ) is a widely consumed leafy vegetable by the rural people in South Africa. Traditional blanching methods (5%, 10% or 20% lemon juice solutions in steam, microwave treatments and hot water bath at 95 °C) on the changes of colour properties, phenolic metabolites, glucosinolates and antioxidant properties were investigated in this study. Blanching at 95 °C in 5% lemon juice solution maintained the chlorophyll content, reduced the difference in colour change ∆E, and increased the total phenolic content and the antioxidant activities (ferric reducing-antioxidant power assay (FRAP) and Trolox equivalent antioxidant capacity (TEAC) assay). The highest concentration of kaempferol-dihexoside, kaempferol-sophoroside, kaempferol hexoside, and ferulic acid was noted in samples blanched in 5% lemon juice, at 95 °C. However, concentrations of kaempferol O -sophoroside- O -hexoside was highest in raw leaf samples. Supervised Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) and the UPLC-MS and chemometric approach showed the acid protocatechuoyl hexose unique marker identified responsible for the separation of the blanching treatments (5% lemon juice at 95° C) and raw leaves. However, other unidentified markers are also responsible for the separation of the two groups (the raw leaves and the hot water moist blanched samples) and these need to be identified. Blanching at 95 °C in 10% lemon solution significantly increased the glucosinolate sinigrin content. Overall blanching at 95 °C in 5% lemon juice solution can be recommended to preserve the functional compounds in Nightshade leaves.

Phyllosphere microorganisms are common contaminants of fruit or vegetable containing foods. The aim of this study was to identify and characterize lactic acid bacteria isolated from fruits and vegetables from Reunion Island, regarding possible application in food. Among 77 isolates, a large diversity of species was observed, with isolates belonging to Lactobacillus plantarum (3 isolates), other species of Lactobacillus (3), Lactococcus lactis (13), Leuconostoc pseudomesenteroides (25), Leuconostoc lactis (1), Leuconostoc mesenteroides (7), Leuconostoc citreum (14), Weissella cibaria (4), Weissella confusa (4), other species of Weissella (2) and Fructobacillus tropaeoli (1). Several of these species, although belonging to lactic acid bacteria, are poorly characterized, because of their low occurrence in dairy products. Lactobacillus, Lactococcus, Leuconostoc and Weissella isolates were classified by (GTG) 5 fingerprinting in 3, 6, 21 and 10 genetic groups, respectively, suggesting a large intra-species diversity. Several Weissella and Lactobacillus isolates were particularly tolerant to acid and osmotic stress, whereas Lc. pseudomesenteroides 60 was highly tolerant to oxidative stress. Isolates of Weissella 30, 64 and 58, Leuconostoc 60 and 12b, Lactobacillus 75 and Fructobacillus 77 present relevant characteristics for their use as starters or as preservative cultures for fruits and vegetables., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The aim of this study was to assess the effect of temperature, solvent (hydroethanolic mixtures) and pH on the recovery of individual phenolic compounds from "horchata" by-products. These parameters were optimized by response surface methodology and triple-TOF-LC-MS-MS was selected as the analytical tool to identify and quantify the individual compounds. The optimum extraction conditions were 50% ethanol, 35 °C and pH 2.5, which resulted in values of 222.6 mg gallic acid equivalents (GAE)/100 g dry matter and 1948.1 µM trolox equivalent (TE)/g of dry matter for total phenolic content (TPC) and trolox equivalent antioxidant capacity (TEAC), respectively. The extraction of phenolic compounds by the conventional solvent method with agitation was influenced by temperature ( p = 0.0073), and more strongly, by the content of ethanol in the extraction solution ( p = 0.0007) while the pH did not show a great impact ( p = 0.7961). On the other hand, the extraction of phenolic acids was affected by temperature ( p = 0.0003) and by ethanol amount ( p < 0.0001) but not by the pH values ( p = 0.53). In addition, the percentage of ethanol influenced notably the extraction of both 4-vinylphenol ( p = 0.0002) and the hydroxycinnamic acids ( p = 0.0039). Finally, the main individual phenolic extracted with hydroethanolic mixtures was 4-vinylphenol (303.3 μg/kg DW) followed by spinacetin3- O -glucosyl-(1→6)-glucoside (86.2 μg/kg DW) and sinensetin (77.8 μg/kg DW).

Nutritional recommendations emphasize fruit and vegetable consumption. This is related to health-benefits associated with bioactive nutritive molecules (nutrients, vitamins, minerals, fibers, …) as well as non-nutritive phytochemicals (phenolic compounds, flavonoids, bioactive peptides, …) content of these types of foods. Fermented fruit or vegetable products are part of various diets worldwide. Lactic acid bacteria (LAB) fermentation is common among the various fermentation processes used. It produces changes in both profile and types of bioactive compounds. Molecules such as bioactive peptides, short chain fatty acids or polysaccharides are generated while sugar content or anti-nutritional compounds are decreased and phenolic compounds are converted to molecules with added biological value. These transformations, associated with prebiotic and/or probiotic potential supply as well as improvement of food components bioaccessibility and bioavailability, result in modifications of health-related properties. Lastly, interactions between ingested fermented food, intestinal microbiota and their correlations to metabolomics profiles and health represent an important perspective deserving to be further explored., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Tropical fruits like pineapple, papaya, mango, and beverages such as green or black teas, represent an underestimated source of antioxidants that could exert health-promoting properties. Most food processing technologies applied to fruit beverages or teas result in an impairment of inherent nutritional properties. Conversely, we hypothesise that lactic acid fermentation may constitute a promising route to maintain and even improve the nutritional qualities of processed fruits. Using specific growth media, lactic acid bacteria were selected from the fruit phyllosphere diversity and fruit juice, with the latter undergoing acidification kinetics analyses and characterised for exopolysaccharide production. Strains able to ferment tropical fruit juices or teas into pleasant beverages, within a short time, were of particular interest. Strains Weissella cibaria 64 and Leuconostoc mesenteroides 12b, able to increase antioxidant activity, were specifically studied as potential starters for lactic fermented pineapple juice.

From 6 samples of tropically grown fruits and leaves, 10 lactic acid bacteria belonging Leuconostoc, Weissella, and Lactobacillus species were isolated and identified by 16S rRNA gene sequencing and (GTG)5 fingerprinting. Acidification kinetics determined from BHI broth cultures showed genus-related patterns. In particular, Weissella cibaria appeared to act as a potent acidifier. Tolerance of isolates to acid, oxidative, or salt stress was highly variable and strain dependent. Isolate S14 (Leuconostoc pseudomesenteroides) growth was not affected by the presence of 0.05% H2O2, while Lactobacillus spp. isolates (S17 and S29) were the most tolerant to pH 4.5. The growth of 4 isolates, S5 (Leuconostoc mesenteroides), S14 and S10 (Leuconostoc pseudomesenteroides), and S27 (W. cibaria), was not affected by 5% NaCl. Nutritional beneficial properties were examined through measurement of antioxidant activities of short-term fermented pineapple juice, such as LDL oxidation and polyphenol content, and through exopolysaccharide formation from sucrose. Two isolates, S14 and S27, increased the antioxidant capacity of pineapple juice. The robust capacity of W. cibaria and of Leuconostoc pseudomesenteroides for vegetable lactic fermentation aimed to ameliorate food nutritional and functional quality was highlighted.

Spoilage of low-acid canned food during prolonged storage at high temperatures is caused by heat resistant thermophilic spores of strict or facultative bacteria. Here, we performed a bacterial survey over two consecutive years on the processing line of a French company manufacturing canned mixed green peas and carrots. In total, 341 samples were collected, including raw vegetables, green peas and carrots at different steps of processing, cover brine, and process environment samples. Thermophilic and highly-heat-resistant thermophilic spores growing anaerobically were counted. During vegetable preparation, anaerobic spore counts were significantly decreased, and tended to remain unchanged further downstream in the process. Large variation of spore levels in products immediately before the sterilization process could be explained by occasionally high spore levels on surfaces and in debris of vegetable combined with long residence times in conditions suitable for growth and sporulation. Vegetable processing was also associated with an increase in the prevalence of highly-heat-resistant species, probably due to cross-contamination of peas via blanching water. Geobacillus stearothermophilus M13-PCR genotypic profiling on 112 isolates determined 23 profile-types and confirmed process-driven cross-contamination. Taken together, these findings clarify the scheme of contamination pathway by thermophilic spore-forming bacteria in a vegetable cannery., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Geobacillus stearothermophilus is the main thermophilic spore former involved in flat sour spoilage of canned foods. Three typing methods were tested and applied to differentiate strains at intra-species level: panC sequence analysis, REP-PCR and M13-PCR. panC gene was highly conserved within the studied strains, suggesting a low intra-specific diversity. This was supported by REP-PCR primary assays and M13-PCR results. M13-PCR profile analysis succeeded in differentiating six closely related groups (at 79% threshold similarity) among 127 strains from a range of spoiled canned food products and from different canneries. Phenotypic traits were investigated among 20 selected strains representing groups and origins. Ranges of growth under different temperatures (from 40 °C to 70 °C), pH (from 5.0 to 6.5), NaCl concentrations (from 1 to 5%) and sporulation conditions poorly differed between strains, but wet heat resistance of spores showed a 20-fold variation between strains. Furthermore, in this study, strains that belonged to the same M13-PCR genetic group did not share phenotypic characteristics or common origin. The work emphasizes a low diversity within the G. stearothermophilus species but data from this study may contribute to a better control of G. stearothermophilus spoilage in canned food., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Although the viable but not culturable (VBNC) state has been studied in detail in bacteria, it has been suggested that maintenance of viability with loss of culturability also exists in eukaryotic cells, such as in the wine spoilage yeast Brettanomyces. To provide conclusive evidence for the existence of a VBNC state in this yeast, we investigated its capacity to become viable and nonculturable after sulfite stress, and its ability to recover culturability after stressor removal. Sulfite addition induced loss of culturability but maintenance of viability. Increasing the medium pH to decrease the concentration of toxic SO(2) allowed yeast cells to become culturable again, thus demonstrating the occurrence of a VBNC state in Brettanomyces upon SO(2) exposure. Relative to culturable Brettanomyces, VBNC yeast cells were found to display a 22% decrease in size on the basis of laser granulometry. Assays for 4-ethylguaiacol and 4-ethylphenol, volatile phenols produced by Brettanomyces, indicated that spoilage compound production could persist in VBNC cells. These morphological and physiological changes in VBNC Brettanomyces were coupled to extensive protein pattern modifications, as inferred by comparative two-dimensional electrophoresis and mass spectrometric analyses. Upon identification of 53 proteins out of the 168 spots whose abundance was significantly modified in treated cells relative to control, we propose that the SO(2)-induced VBNC state in Brettanomyces is characterized by a reduced glycolytic flux coupled to changes in redox homeostatis/protein turnover-related processes. This study points out the existence of common mechanisms between yeast and bacteria upon entry to the VBNC state., (Copyright © 2012 Elsevier Ltd. All rights reserved.)