查看更多>>摘要：In order to study the effect of different initial pH values on heat resistance of the strain, the changes in heat stress survival rates of Lactobacillus plantarum LIP-1 and its potential influencing mechanisms were investigated under different initial pH values. The results showed that the growth L. plantarum LIP-1 did not significantly differ according to initial pH value (P > 0.05), but there were significant differences in heat stress survival rates among initial pH values (P < 0.05). Further analysis revealed that a suitable initial pH value could improve the relative proportion of unsaturated fatty acids in the cell membrane and increase the ratio of unsaturated to saturated fatty acids (U/S), reduce the thermal damage to cell membrane, and improve heat stress survival of the strain. The adjustment of cell membrane fatty acid composition is related to the acidic stress environment caused by the rapid growth of L. plantarum LIP-1 under suitable initial pH conditions. The results confirmed that a suitable initial pH value could improve the heat resistance of the strain. Accordingly, this study provides a theoretical reference for improving the spray drying of probiotics by changing the culture conditions.
Fadzil, Muhammad Fakhrurazi AhmadAnnuar, Mohamad Suffian MohamadIshak, Khairul Anwar
9页
查看更多>>摘要：A sugar-fatty acid ester, named glucose monooleate (GluO) was synthesized using commercial immobilized lipase B from Candida antarctica. A preparation of oil-in-water (O/W) emulsion using a combination of non-ionic surfactant mixture, i.e., GluO and Cremophor EL (CrEL), and different vegetable oils, i.e., coconut, sunflower, olive, palm and jojoba oils through phase inversion emulsification (PIE) was investigated. A baseline formulation was carried out to obtain an optimal ratio of surfactant-to-oil (S:O) and Cremophor EL-to-Glucose monooleate (CrEL:GluO) with coconut oil as the carrier oil. GluO proves to be an effective co-surfactant when a high amount of oil was incorporated. At 60:40 of S:O and CrEL:GluO, coconut and sunflower oil were emulsified into nanosized oil droplets with the sizes (in diameter) of 36 +/- 1.5 nm (PDI = 0.17 +/- 0.05) and 42 +/- 1.3 nm (PDI = 0.18 +/- 0.07), respectively. In contrast, olive, palm and jojoba oils produced coarse emulsions with larger oil particles with the sizes of 238 +/- 22, 295 +/- 41 and 312 +/- 63 nm, respectively. Furthermore, at 60:40 of S:O and CrEL:GluO, up to 0.98 mg of p-carotene (approximate to 0.03% of total emulsion weight) can be encapsulated within coconut oil droplets of the 0/W system with an average size below 100 nm. The emulsification process was investigated through Fourier-transform infrared (FTIR) spectroscopy, small-wide angle X-ray (SWAX) and optical polarizing microscopy (OPM) analyses. Possible effects of the surfactant mixture (CrEL-GluO) and different vegetable oils on the emulsion preparation were also discussed.
Del Juncal-Guzman, DianaHernandez-Maldonado, Luz M.Sanchez-Burgos, Jorge A.Gonzalez-Aguilar, Gustavo A....
8页
查看更多>>摘要：Pineapple (Ananas comosus) is a widely consumed tropical fruit. UV-C irradiation reduces the microbial load of fruits and contributes to the increase their content of phenolic compounds (PCs). Snack-bars were prepared batch using UV-C irradiated pineapple slices (irradiated pineapple bar, IPB) or with non-irradiated pineapple slices (non-irradiated pineapple bar, NIPB). Both snacks-bar samples were submitted to simulated gastrointestinal digestion and in vitro colonic fermentation, to evaluate the in vitro bioaccesiblility of PCs present in these fruit-based products. The bioaccesibility of PCs in both samples at the end of the digestion process was 45%. PCs in the intestinal phase increased about 52.7% (NIPB) and 62.8% (IPB) compared to the gastric phase, a change that indicates how many of the PCs cross the intestinal barrier. Twenty-six different compounds, including flavonoids, hydroxycinnamic and phenolic acids were identified in the digested samples. The non-digestible fraction submitted to colonic fermentation, was rich in flavonoids, mostly gallocatechin. This compound was degraded and biotransformed by the gut microbiota producing different compounds, including 3-hydroxybenzoic and 4-hydmxyphenylacetic acids. The study of the bioconversion of PCs present in different food matrices stress the relevance of the metabolites produced during the colonic fermentation.
查看更多>>摘要：Lepidium latifolium L. from Ladakh Himalayas is a high source of 2-propenyl glucosinolate (GLS). To utilize it as a functional food, differently aged sprouts (1st-, 2nd-, 3rd-, 4th-, and 8th-week) were evaluated for phytochemical, nutritional, and antioxidant properties. A combination of 2-propenyl and benzyl GLS was found in significantly (p <= 0.05) higher quantity during the first four stages. Benzyl GLS decreased during the 8th-week stage, with a concomitant increase in 2-propenyl GLS. The content of GLSs was found under the transcriptional regulation of the MYB transcription factors. Despite the similar metabolic content of GLSs, higher myrosinase activity during the 3rd-week might increase their bioavailability. Lepidium sprouts also contain higher amounts of nutritionally important vitamin C, camtenoids, phenolic acids, and fatty acids than observed in other Brassica species. The antioxidant potential in sprouts corroborated with the content of phenols and flavonoids and was higher during the first three weeks. Our results suggest that sprouts during the 3rd-week stage showed a unique combination of GLSs and qualitative and quantitative phytochemical superiority, hence could be promoted as a functional food.
查看更多>>摘要：Tuning structure of gelatin edible films by crosslinking with oxidized polysaccharides is a highly interesting approach, as thereby the random coil structure of gelatin changes towards a covalent network and thus the properties can be tailored. With this aim, a series of pullulan dialdehyde (PDA) with different molecular weights and aldehyde contents were successfully synthesized by periodate oxidation of pullulan, and subsequently being used for crosslinking gelatin edible films. The inclusion of PDA in gelatin films induced chemical crosslinking between the protein chains and consequently improved their water vapor barrier property and thermal properties. The water solubility of gelatin films decreased from 42.3 +/- 2.1% to 18.7 +/- 0.5% after PDA crosslinking, while the tensile strength of the crosslinked gelatin films was about 2.7 times that of neat gelatin film. Furthermore, PDA crosslinking provoked a significant browning coloration of the gelatin films, accompanied by a significant improvement in UV light barrier property. The results also indicated that the molecular weight of PDA might play an important role in affecting the network structure and properties of gelatin films. Collectively, PDA crosslinking can be considered to be a potential alternative for tuning structure and properties of gelatin edible films.
查看更多>>摘要：The impact of fungal post-harvest infection of apple on the chemical composition of cider was investigated through a comparative analysis of ciders obtained from apples (Gala variety) separately infected by five fungal species (Alternaria alternata, Botrytis cinerea, Diplodia seriata, Monilinia fructigena, and Penicillium expansum) and cider from sound apples. The content of several flavor-active molecules belonging to different chemical groups, such as alcohols, esters, acids, aldehydes, phenols, and lactones, significantly varied among ciders. Particularly, cider from sound apples had a higher concentration of ethyl ester acetate, fatty acid ethyl esters and fatty acids, molecules that contribute to fruity and sweet scent. Principal component analysis well discriminated ciders, evidencing species-specific fungal effect. Differences in precursor availability in juices and biosynthesis pathways in fungi could explain changes in aroma profile of ciders. This study provides information on the potential risk to produce cider from infected apples due to the possible quality depreciation.
查看更多>>摘要：Consumers demand for good appearance and safe fresh-cut fruits without synthetic preservatives. Phenolic compounds from makiang seeds were extracted and applied as a natural preservative. Makiang seed extract (MKSE) was treated with 5 various amount of Diaiont HP-2MG, a macro porous resin, to enrich the phenolic compound content. The application of 0.375 g Diaion (R) to 1 mL of 12.5 mg mL(-1) MKSE was suitable for adsorbing the phenolic compounds. The eluent of 70% ethanol was able to release phenolic compounds with the highest recovery rate (61.22%). After drying, the phenolic enriched MKSE (PMKSE) contained 97.24% phenolic compounds and 4.99% flavonoids. The antagonistic effect of the MKSE was increased with the enrichment of phenolic content. The fresh cut cantaloupe (FCC) soaked with 1MBC PMKSE reduced the number of bacterial count on FCC, but affected the FCC color. The equal volume of 3.13 mg mL(-1) PMKSE and 6.25% citric acid (MC) could reduce the number of spiked E. coli on FCC to 1.66 log CFU g(-1) and retard the growth of pathogenic bacteria without significantly change in color. The MC had a potential to be applied for maintaining the bacterial quality and color of fresh-cut produce and minimal processed foods.
查看更多>>摘要：This study aimed to assess the effects of different treatments [citric acid (CA), perforated and unperforated, packaging (17 and 23 mu film thickness)] on weight loss, respiration and decay rate, color, bioactive compounds, dry matter, ash and protein of Cantharellus cibarius mushroom during the cold storage [at 0 +/- 0.5 degrees C and 90 +/- 5% relative humidity (RH) for 12 days (d)]. Modified atmosphere packaging (MAP) significantly reduced weight loss and decay compared to control. With the progress of the storage period, the significant increases were observed in protein, ash, dry matter, vitamin C, total phenolic and antioxidant activity. At the end of storage, citric acid+23 mu m thick non-perforated low-density polyethylene [LDPE (CANP23)] treatment for the highest protein; control and distilled water+23 mu m thick non-perforated LDPE (NP23) for the highest vitamin C; citric acid+17 mu m thick non-perforated LDPE (CAP17) for the highest total phenolics; NP23 for the highest antioxidant activity was determined. As a result, it was revealed that the weight loss and decay rate of Cantharellus cibarius can be significantly reduced with MAP and more caution should be taken regarding the citric acid (CA) application and the studies should be conducted to find the appropriate dose.
查看更多>>摘要：This study was to investigate the succession of the bacterial community in Harbin dry sausages during fermentation and its correlation to the sausage flavour. The results showed that Staphylococcus count increased but the moisture content and water activity decreased (P < 0.05). The lactic acid bacteria count first increased and then decreased, while the pH showed an opposite trend during a twelve-day fermentation (P < 0.05). According to a single molecule real time sequencing analysis, Lactobacillus sakei and Staphylococcus xylosus were the predominant bacterial species over the entire fermentation period. A total of 79 volatile compounds were detected using the headspace solid phase microextraction gas chromatography-mass spectrometry. Furthermore, the correlation between the core bacteria (top 30) and the major volatile compounds was explored, which highlighted that three bacterial species (Lb. sakei, S. xylosus and Weissella hellenica) were significantly correlated with the major volatile compounds, such as 2,3-butanediol, ethanol, 3-hydroxy-2-butanone, ethyl hexanoate and ethyl lactate. The results may provide a theoretical basis for improving the flavour and overall quality of dry sausage.
Carlos Carmona, JuanRobert, PazVergara, CristinaSaenz, Carmen...
7页
查看更多>>摘要：There is an increasing interest in the use of natural food colorants to substitute synthetic dyes that are health harmful. In this study, encapsulation conditions of yellow-orange cactus pear Opuntia ficus-indica pulp (P), were determined using maltodextrin (MD) as the encapsulating agent (EA). The effect of three encapsulating agents (cactus mucilage (M), MD, and mucilage-maltodextrin (M+MD) blend) on microparticle's characteristics, stability, and performance as a colorant in yogurt was assessed at optimal conditions determined by Response Surface Methodology. Optimal conditions for encapsulation with MD were inlet air temperature 150 degrees C and a 3:1 ratio, where pulp:encapsulating agent ratio had more influence than the temperature in the yield during encapsulation. Indicaxanthin encapsulation efficiency and yield were 100% and 51.2% (P-MD), 87% and 7% (P-M), and 93% and 11% (P-M+MD), respectively. P-MD system showed higher indicaxanthin stability and less color change stored at 60 degrees C. However, P-MD and P-M+MD microparticles were successfully tested as colorants in yogurt, and both colorants showed similar performance and stability (over 80% indicaxanthin retention). Cactus cladode mucilage with the addition of maltodextrin could be the encapsulating agent for yellow-orange cactus pear pulp, thus providing pigment protection as a yellow colorant for yogurt.
NSTL
Elsevier