Phenolic composition of grape pomace and its metabolism.

Grape pomace is the most important residual after wine making, and it is considered to be a very abundant source for the extraction of a wide range of polyphenols. These polyphenols exhibit a variety of bioactivities, such as antioxidant, anti-inflammatory, and anti-cancer. They are also beneficial in alleviating metabolic syndrome and regulating intestinal flora, etc. These health effects are most likely contributed by polyphenol metabolite, which are formed by the grape pomace phenolics after a complex metabolic process in vivo. Therefore, understanding the phenolic composition of grape pomace and its metabolism is the basis for an in-depth study of the biological activity of grape pomace polyphenols. In this paper, we first summarize the composition of phenolics in grape pomace, then review the recent studies on the metabolism of grape pomace phenolics, including changes in phenolics in the gastrointestinal tract, their pharmacokinetics in the systemic circulation, the tissue distribution of phenolic metabolites, and the beneficial effects of metabolites on intestinal health, and finally summarize the effects of human health status and dietary fiber on the metabolism of grape polyphenols. It is expected to provide help for the in-depth research on the metabolism and biological activity of grape pomace polyphenol extracts, and to provide theoretical support for the development and utilization of grape pomace.

Study of Inheritance and Linkage of Virulence Genes in a Selfing Population of a Pakistani Dominant Race of Puccinia striiformis f. sp. tritici.

Wheat stripe rust is a severe threat of almost all wheat-growing regions in the world. Being an obligate biotrophic fungus, Puccinia striiformis f. sp. tritici (PST) produces new virulent races that break the resistance of wheat varieties. In this study, 115 progeny isolates were generated through sexual reproduction on susceptible Himalayan Berberis pseudumbellata using a dominant Pakistani race (574232) of PST. The parental isolate and progeny isolates were characterized using 24 wheat Yr single-gene lines and ten simple sequence repeat (SSR) markers. From the one-hundred-and-fifteen progeny isolates, 25 virulence phenotypes (VPs) and 60 multilocus genotypes were identified. The parental and all progeny isolates were avirulent to Yr5, Yr10, Yr15, Yr24, Yr32, Yr32, YrSp, YrTr1, YrExp2, Yr26, and YrTye and virulent to Yr1, Yr2, Yr6, Yr7, Yr8, Yr9, Yr17, Yr25, Yr27, Yr28, YrA, Yr44, and Yr3. Based on the avirulence/virulence phenotypes, we found that VPs virulent to Yr1, Yr2, Yr9, Yr17, Yr47, and YrA were controlled by one dominant gene; those to YrSp, YrTr1, and Yr10 by two dominant genes; and those to YrExp2 by two complementary dominant genes. The results are useful in breeding stripe rust-resistant wheat varieties and understanding virulence diversity.

Mycotoxin patulin in food matrices: occurrence and its biological degradation strategies.

Patulin is a mycotoxin produced by a number of filamentous fungal species. It is a polyketide secondary metabolite which can gravely cause human health problems and food safety issues. This review deals with the occurrence of patulin in major food commodities from 2008 to date, including historical aspects, source, occurrence, regulatory limits and its toxicity. Most importantly, an overview of the recent research progress about the biodegradation strategies for contaminated food matrices is provided. The physical and chemical approaches have some drawbacks such as safety issues, possible losses in the nutritional quality, chemical hazards, limited efficacy, and high cost. The biological decontamination based on elimination or degradation of patulin using yeast, bacteria, and fungi has shown good results and it seems to be attractive since it works under mild and environment-friendly conditions. Further studies are needed to make clear the detoxification pathways by available potential biosorbents and to determine the practical applications of these methods at a commercial level to remove patulin from food products with special reference to their effects on sensory characteristics of foods.

Identification of Berberis Species Collected from the Himalayan Region of Pakistan Susceptible to Puccinia striiformis f. sp. tritici.

Puccinia striiformis f. sp. tritici (Pst), the stripe rust pathogen infecting cereal crops and grasses, was believed to have a hemicyclic life cycle consisting of uredinial and telial stages before the recent discovery of barberry (Berberis spp.) as an alternate (aecial) host for the fungus. This discovery has improved the understanding of the biology of the stripe rust pathogen. The Himalayan and near-Himalayan regions of Pakistan, China, and Nepal are considered as the center of diversity for Pst pathogen. High genetic diversity has been reported in these areas, probably resulting from the sexual reproduction of the stripe rust fungus. To determine if Berberis species growing in Pakistan are susceptible to Pst, we collected seeds of five species and two subspecies from the Himalayan region in 2016 and inoculated the seedlings with germinated teliospores of a Pakistani Pst isolate under controlled conditions. Pycnia and aecia were produced on all inoculated plants of these species and subspecies, and were demonstrated as Pst by successful infection of wheat plants with aeciospores. This study showed that the tested Pakistani Berberis species and subspecies are susceptible to Pst under controlled conditions.

Biosafety measures for Alicyclobacillus spp. strains across various levels of biohazard.

Alicyclobacillus bacteria are important contaminants in the beverage industry because their spores remain in the product after usual pasteurization. At the same time, their impact on human health has yet to be characterized, as it is generally assumed to be low or non-existent. However, these bacteria are causing quality concerns mainly due to odor and taste changes of the product. Since potential health effects are not precisely known, an experimental assessment was performed, including a biosafety assessment of six viable and non-viable vegetative and spore forms of Alicyclobacillus spp. strains using cell cultures and rodent study. The monolayer of Caco-2 (Cancer coli-2) cells was investigated for its adsorption effect on the epithelium of the small intestine of mice. Lactate dehydrogenase leakage (LDH) and transepithelial electrical resistance (TEER) tests were used to ensure the integrity of the cell membrane and tight junctions. The methylthiazole tetrazolium bromide (MTT) assay examined in vitro cytotoxicity in Caco-2 and HepG2 cell lines. The hemolysis of erythrocytes was spectrophotometrically measured. The results showed negligible cytotoxicity or non-toxic response in mice. In conclusion, Alicyclobacillus spp. exhibited biocompatibility with negligible cytotoxicity and minimal safety concerns.

Alternate Hosts of Puccinia striiformis f. sp. tritici and Their Role.

Understanding the interactions between the host and the pathogen is important in developing resistant cultivars and strategies for controlling the disease. Since the discovery of Berberis and Mahonia spp. as alternate hosts of the wheat stripe rust pathogen, Puccinia striiformis Westend. f. sp. tritici Erikss. (Pst), their possible role in generating new races of Pst through sexual reproduction has become a hot topic. To date, all the investigations about the role of alternate hosts in the occurrence of the wheat stripe rust epidemics revealed that it depends on alternate host species and environmental conditions. In this review, we summarized the current status of alternate hosts of Pst, their interactions with the pathogen, their importance in genetic diversity and disease epidemics. Most importantly, the recent research progress in understanding the role of alternate hosts of Pst is provided.

Fourier Transform Near-Infrared Spectroscopy and Chemometrics To Predict Zygosacchromyces rouxii in Apple and Kiwi Fruit Juices.

This study investigated the capability of near-infrared spectroscopy (NIRS) to predict the concentration of Zygosaccharomyces rouxii in apple and kiwi fruit juices. The yeast was inoculated in fresh kiwi fruit juice ( n = 68), reconstituted kiwi juice ( n = 85), and reconstituted apple juice ( n = 64), followed by NIR spectra collection and plate counting. A principal component analysis indicated direct orthogonal signal correction preprocessing was suitable to separate spectral samples. Parameter optimization algorithms increased the performance of support vector machine regression models developed in a single variety juice system and a multiple variety juice system. Single variety juice models achieved accurate prediction of Z. rouxii concentrations, with the limit of quantification at 3 to 15 CFU/mL ( R2 = 0.997 to 0.999), and the method was also feasible for Hanseniaspora uvarum and Candida tropicalis. The best multiple variety juice model obtained had a limit of quantification of 237 CFU/mL ( R2 = 0.961) for Z. rouxii. A Bland-Altman analysis indicated good agreement between the support vector machine regression model and the plate counting method. It suggests that NIRS can be a high-throughput method for prediction of Z. rouxii counts in kiwi fruit and apple juices.

Effective Adsorption of Patulin from Apple Juice by Using Non-Cytotoxic Heat-Inactivated Cells and Spores of Alicyclobacillus Strains.

Patulin (PAT) is a major threat to many food products, especially apple and apple products, causing human health risks and economic losses. The aim of this study was to remove PAT from apple juice by using the heat-inactivated (HI) cells and spores of seven Alicyclobacillus strains under controlled conditions. The HI cells and spores of seven strains adsorbed PAT effectively, and the HI cells and spores of Alicyclobacillus acidocaldarius DSM 451 (A51) showed maximum PAT adsorption capacity of up to 12.621 µg/g by HI cells and 11.751 µg/g by HI spores at 30 °C and pH 4.0 for 24 h. Moreover, the PAT adsorption process followed the pseudo-first order kinetic model and the Freundlich isotherm model; thermodynamic parameters revealed that PAT adsorption is a spontaneous exothermic physisorption process. The results also indicated that PAT adsorption is strain-specific. The HI cells and spores of Alicyclobacillus strains are non-cytotoxic, and the bioadsorption of PAT did not affect the quality of the juice. Furthermore, the cell wall surface plays an important role in the adsorption process.