Scientific, Health and Social Aspects of the Food Industry

This book presents the wisdom, knowledge and expertise of the food industry that ensures the supply of food to maintain the health, comfort, and wellbeing of humankind. The global food industry has the largest market: the world population of seven billion people. The book pioneers life-saving innovations and assists in the fight against world hunger and food shortages that threaten human essentials such as water and energy supply. Floods, droughts, fires, storms, climate change, global warming and greenhouse gas emissions can be devastating, altering the environment and, ultimately, the production of foods. Experts from industry and academia, as well as food producers, designers of food processing equipment, and corrosion practitioners have written special chapters for this rich compendium based on their encyclopedic knowledge and practical experience. This is a multi-authored book. The writers, who come from diverse areas of food science and technology, enrich this volume by presenting different approaches and orientations

Characterization of a New Saccharomyces cerevisiae Isolated From Hibiscus Flower and Its Mutant With L-Leucine Accumulation for Awamori Brewing

Since flavors of alcoholic beverages produced in fermentation process are affected mainly by yeast metabolism, the isolation and breeding of yeasts have contributed to the alcoholic beverage industry. To produce awamori, a traditional spirit (distilled alcoholic beverage) with unique flavors made from steamed rice in Okinawa, Japan, it is necessary to optimize yeast strains for a diversity of tastes and flavors with established qualities. Two categories of flavors are characteristic of awamori; initial scented fruity flavors and sweet flavors that arise with aging. Here we isolated a novel strain of Saccharomyces cerevisiae from hibiscus flowers in Okinawa, HC02-5-2, that produces high levels of alcohol. The whole-genome information revealed that strain HC02-5-2 is contiguous to wine yeast strains in a phylogenic tree. This strain also exhibited a high productivity of 4-vinyl guaiacol (4-VG), which is a precursor of vanillin known as a key flavor of aged awamori. Although conventional awamori yeast strain 101-18, which possesses the FDC1 pseudogene does not produce 4-VG, strain HC02-5-2, which has the intact PAD1 and FDC1 genes, has an advantage for use in a novel kind of awamori. To increase the contents of initial scented fruity flavors, such as isoamyl alcohol and isoamyl acetate, we attempted to breed strain HC02-5-2 targeting the L-leucine synthetic pathway by conventional mutagenesis. In mutant strain T25 with L-leucine accumulation, we found a hetero allelic mutation in the LEU4 gene encoding the Gly516Ser variant α-isopropylmalate synthase (IPMS). IPMS activity of the Gly516Ser variant was less sensitive to feedback inhibition by L-leucine, leading to intracellular L-leucine accumulation. In a laboratory-scale test, awamori brewed with strain T25 showed higher concentrations of isoamyl alcohol and isoamyl acetate than that brewed with strain HC02-5-2. Such a combinatorial approach to yeast isolation, with whole-genome analysis and metabolism-focused breeding, has the potentials to vary the quality of alcoholic beverages

Overexpression and characterisation of heterologous esterases from a metagenomic library

Submitted in fulfilment of the academic requirements for the degree of Master of Science in School of Molecular and Cell biology University of the Witwatersrand Johannesburg, South AfricaEsterases are hydrolytic enzymes that have many industrial applications. They are used in food, pharmaceutical, pulp and paper, cosmetics, biofuels and many other industries. This gives research of these enzymes major importance. Esterase genes received from CSIR Biosciences were cloned in E. coli DH5α cells. The plasmids carrying these genes were pET20b(+) for genes named Est1, Est2, Est3, Est4, Est5, Est6, Est7, Est8, Est9, Est10, Est12, Est13, Est14 and pET28a(+) for Est11. These plasmids were extracted from the cloning host and transformed into the expression host which was E. coli BL21. The cells were then induced for expression and the presence of the protein bands representing the products of expression were confirmed by running the crude enzyme extract on SDS-Page. The enzyme extracts were tested for activity using pNp-acetate. All 14 esterases were active and they were characterised in terms of pH optima, temperature optima and kinetics. The enzymes showed a pH range of 6.0 to 9.0 and temperature range of 30°C to 50°C. The enzymes were investigated for substrate specificity and they showed a greater preference for short acyl chain substrates over long acyl chain substrates. Further testing was done for activity of the enzymes using α-naphthylbutyrate and naphthol AS-D chloroacetate alongside lipases. A total of 87 enzymes were tested using these colorimetric assays and 36 of the enzymes were found to be active including all 14 esterases. These 36 enzymes were tested for use in enzymatic resolution of three different chemical compounds available as racemic mixtures. No success was observed for two of the compounds but one of them showed some enantioselectivity. This research will be furthered on at large scale to allow continued synthesis of potential HIV-1 protease inhibitors

New Insights into Food Fermentation

This reprint is dedicated to new insights into food fermentation. The goal of this reprint was to broaden the current knowledge on advanced approaches concerning food fermentation, gathering studies on conventional and unconventional food matrix fermentation, functional compounds obtained through fermentation, fermentations increasing quality and safety standards, as well as papers presenting innovative approaches shedding light on the microbial community that characterizes fermented foods