RECOVERY OF PHYTOCHEMICAL RICH FRACTIONS FROM WINEMAKING BYPRODUCTS FOR NOVEL FOOD APPLICATIONS
Tesi di Dottorato
Data di Pubblicazione:
2014
Citazione:
RECOVERY OF PHYTOCHEMICAL RICH FRACTIONS FROM WINEMAKING BYPRODUCTS FOR NOVEL FOOD APPLICATIONS / S.c.s.h. Pedapati ; tutor: V. Lavelli ; co-tutor: P. Simonettii ; coordinatore: M. G. Fortina. Università degli Studi di Milano, 2014 Dec 05. 27. ciclo, Anno Accademico 2014. [10.13130/pedapati-siva-charan-sri-harsha_phd2014-12-05].
Abstract:
The food industry is facing the significant challenge of developing new ingredients and foods addressing prevention of the major chronic diseases, while optimizing processing technologies in order to achieve a sustainable use of natural resources. Grape pomace, the byproduct of winemaking, is available on a large scale and is comprised of various compounds associated with potential health benefits. In this context, the overall PhD project aimed at developing an integrated strategy for recovery and reuse of value added fractions of winemaking byproducts in the food system.
Grape pomace samples, differing for the varieties and winemaking conditions were collected from winemaking processes and evaluated for valuable components, i.e, dietary fibre, total phenolics, soluble and insoluble proanthocyanidins (n-butanol/HCl assay), individual phenolic compouns (UPLC-DAD-MS), tocopherol and tocotrienol contents (HPLC with fluorimetric detection). This led to the design of a comprehensive recovery plan, bringing about the overall value of winemaking byproducts.
The aim of targeting a specific health functionality by grape phenolics was tackled in chapter 1, focused on their protective effects on hyperglyacemia induced damage. In the current scenario, prevention of diabetes complications is of utmost importance due to an upsurge in the prevalence of this disease among the world population (with an estimation of 300 million cases that could be registered by 2030). In vivo study has shown that phenolics can prevent the leading cause of hyperglycemia damage, i.e., non-enzymatic protein glycaton, most likely via radical scavenging, metal chelation and carbonyl trapping. However to target this effect, there is a need for phenolic fractions with high concentration and efficiency. An in vitro model system using fructose as glycating agent and bovine serum albumin as target was set up. The protective ability of grape skin phenolics was evaluated with both a novel methodological approach by 2D-SDS/IEF-PAGE and quantification of the formation of advanced glycation end-products by fluorescence measurements. Structural modifications of BSA upon glycation, as evidenced by changes in pI and Mr were found to be inhibited by the grape skin extracts. The antiglycation activity ranking was: quercetin-3-O-glucoside > malvidin-3-O-glucoside > catechin > procyanidin A2 >> aminoguanidine (reference drug). Despite variability in phenolic content (in the range 4.6-53.6 g gallic acid equivalents (GAE)/kg) and composition among grape skin extracts, upon equalization of the phenolic content, similar antiglycation properties were observed. Grape skins (I50 in the range 9.2-20 µg GAE/mL) were more efficient than the commercial nutraceutical products Leucoselect® (I50 38 µg GAE/mL) and Pycnogenol® (I50 34 µg GAE/mL) and hence could provide cost-effective antiglycation agents, to be used either as food ingredients or as nutraceutical preparations.
The task of designing new foods by the incorporation of grape skins, which can deliver both dietary fibers and phenolics, was examined in chapter 2. Grape skins have been proposed as ingredients for “solid” or “gel-like” foods, but knowledge on their possible application in complex food fluids that could represent low caloric vehicle for value added ingredients is lacking. Hence, a tomato puree added with grape skins was studied as a model application and a production process was designed to increase potential health benefit of this product with maximum consumers’ liking.
To optimize grape skin ingredient incorporation in tomato puree, six formulations (3% dietary fibre and ~ 0.7% proanthocyanidins) varying in the particle size (assessed by a laser granulometer) were considered in parallel. Stabilization
Tipologia IRIS:
Tesi di dottorato
Keywords:
winemaking; byproducts; phenolics; tocols; dietary fibre; food innovation; food process optimization
Elenco autori:
S.C.S.H. Pedapati
Link alla scheda completa:
Link al Full Text: