Nirmal K. Sinha

Handbook of vegetables and vegetable processing

Description: Vegetables are an important article of commerce both in developed and developing economies. Many studies point to importance of vegetables in our diet. Handbook of Vegetables and Vegetable Processing serves as a reference handbook on vegetables and vegetable processing containing the latest developments and advances in this fast growing field. The book can be considered as a companion to Y. H. Hui s popular Handbook of Fruits and Fruit Processing (2006). Handbook of Vegetables and Vegetable Processing is contemporary in scope, with in–depth coverage of new interdisciplinary developments and practices in the field of vegetables emphasizing processing, preservation, packaging, and nutrition and food safety. Coverage includes chapters on the biology, horticultural biochemistry, microbiology, nutrient and bioactive properties of vegetables and their significant commercialization by the food industry worldwide. Full chapters are devoted to major vegetables describing aspects ranging from chemistry to processing and preservation. World–renowned editors and authors have contributed to this essential handbook on vegetables and their production, technology, storage, processing, packaging, safety and commercial product development.

Pyruvate and flavor development in macerated onions (Allium cepa L.) by γ-glutamyl transpeptidase and exogenous C-S lyase

Abstract Effect of γ-glutamyl transpeptidase in conjunction with exogenous C-S lyase on pyruvate content in macerated onion and flavor profile was studied. Pyruvate production of 2.5-fold greater than that of the control was obtained in γ-glutamyl transpeptidase and exogenous C-S lyase treated onions held for 20 h at 37 °C. Relative abundance of flavor compounds in Spartan Banner, a pungent onion, varied from a yellow sweet salad-type onion. The effect of γ-glutamyl transpeptidase and exogenous C-S lyase on onion flavor profile was shown by a shift of major components from methyl propyl disulfide, methyl propenyl trisulfide, dimethyl tetrasulfide and propyl 1-propenyl trisulfide, into new major components, methyl 1-propenyl disulfide, dipropyl disulfide, propyl 1-propenyl disulfide, methyl 1-propenyl trisulfide, and propyl 1-propenyl trisulfide. This increase in 1-propenyl containing flavor compounds may effect overall flavor of γ-glutamyl transpeptidase and exogenous C-S lyase treated onion extracts.

Effects of flour chlorination on soft wheat gliadins analyzed by reversed-phase high-performance liquid chromatography, differential scanning calorimetry and fluorescence spectroscopy

Abstract Chlorinated soft wheat flours produce better quality cakes. In this study, changes in surface hydrophobicity of gliadins due to flour chlorination were analyzed. Results obtained from RP-HPLC of gliadins showed intervarietal differences, but intravarietal differences in the gliadin patterns of chlorinated and unchlorinated flours were difficult to discern because of the large number of peaks eluted. However, three-dimensional plots of retention time, wavelength and absorbency showed differences among gliadin patterns of unchlorinated and chlorinated flours within a variety, suggesting conformational changes and consequently alteration in hydrophobicity of gliadins due to chlorination. The DSC analyses of gliadins extracted from unchlorinated and chlorinated flours showed higher denaturation peak transition temperatures (Td) and lower enthalpies of transition (ΔH) in some varieties, indicating hydrophobicity and conformational changes. Fluorescence spectroscopy measurements with an extrinsic probe, 1-anilino-8-naphthalene sulfonic acid (ANS), showed increases in hydrophobicity of gliadins from chlorinated flours, confirming conformational changes in gliadins due to chlorination.