Physicochemical properties and structural characteristics of soluble dietary fibers from yellow and purple fleshed potatoes by-product

Properties of plant-derived soluble dietary fibers for fiber-enriched foods: A comparative evaluation

Plant-derived soluble dietary fibers (SDF) have many important physiological functions and the applications of SDF vary based on their properties, which are worth further investigating for fiber-enriched food production. In this study, SDF derived from konjac, apple, chicory, flaxseed, orange, psyllium seed, soybean and oat were purified, and their structural, physicochemical and functional properties were systematically evaluated. Monosaccharide composition analysis showed that these SDF belonged to heteropolysaccharides, of which konjac, psyllium seed, apple, soybean and oat SDF were glucomannan, arabinoxylan, pectin, arabinogalactan and glucan, respectively. The molecular weight of konjac glucomannan (KGM, 5.22 × 10⁶ Da) was the highest, and inulin, soybean arabinogalactan (SA) and oat glucan (OG) had higher water solubility. Moreover, KGM, apple pectin (AP), flaxseed SDF (FS) and psyllium seed arabinoxylan (PA) exhibited better water-holding capacity, swelling capacity, emulsifying activity and stability. Rheological studies and texture profile analysis suggested that KGM had the best viscosity and gelation ability. In addition, AP and orange SDF (OS) showed better α-amylase inhibitory activity, while OS and KGM had higher pancreatic lipase inhibitory activity. Also, KGM and FS displayed fine cholesterol absorption capacity. To summary, these functional properties illustrated the feasibility of SDF to regulate blood sugar and blood lipid levels.

Nutritional, Physico-Chemical and Mechanical Characterization of Vegetable Fibers to Develop Fiber-Based Gel Foods

The aim of this research was to evaluate the nutritional and physico-chemical properties of six different vegetable fibers and explore the possibility of using them as a thickener or gelling agent in food. To determine the technological, nutritional and physical parameters, the following analyses were carried out: water-holding capacity, water retention capacity, swelling, fat absorption capacity, solubility, particle size, moisture, hygroscopicity, pH, water activity, bulk density, porosity, antioxidant activity, phenolic compounds and mineral content. Gels were prepared at concentrations from 4% to 7% at 5 °C and analyzed at 25 °C before and after treatment at 65 °C for 20 min. A back extrusion test, texture profile analysis and rheology were performed and the pH value, water content and color were analyzed. As a result, all the samples generally showed significant differences in all the tested parameters. Hydration properties were different in all the tested samples, but the high values found for chia flour and citrus fiber are highlighted in functional terms. Moreover, chia flour was a source of minerals with high Fe, Mn and Cu contents. In gels, significant differences were found in the textural and rheological properties among the samples, and also due to the heat treatment used (65 °C, 20 min). As a result, chia flour, citrus, potato and pea fibers showed more appropriate characteristics for thickening. Moreover, potato fiber at high concentrations and both combinations of fibers (pea, cane sugar and bamboo fiber and bamboo, psyllium and citric fiber) were more suitable for gelling agents to be used in food products.

METHODS FOR DETERMINING THE CHARACTERIZATION OF MASHES WITH FIBER FOR SEMI-FINISHED PRODUCTS ON THE MILK-PROTEIN BASE

The aim of the work is to elaborate effective methods that characterize mashes of semi-products with potato fiber after thermal processing for avoiding excessive densification of products and stabilization of qualimetric parameters. The article presents main methods for determining characteristics of mashes with potato fiber for thermally processed semi-products. Methods for studying the ability of dietary fiber «Potex» to change the effective viscosity and water-retaining capacity of multicomponent systems are offered. Values that characterize deviations of parameters at using white sugar the dehydrating capacity and egg mélange, which influence is changed by the aforesaid parameters at thermal processing, are obtained. The effectiveness of determining the water activity value аw for specifying storage parameters of mashes with potato fiber for semi-products is confirmed. Qualimetric parameters of experimental samples are obtained. Least mass losses at frying (155±5 °С) and baking (185±5 °С) were observed at adding maximal amount of «Potex» (2.0 %) and fixed at level 4.3±0.2 % and 6.2±0.1 % respectively. Introduction of dietary fiber decreases a content of free water in mashes for semi-products and, as a result, there is observed a mass loss decrease at thermal processing. It allows to stabilize qualimetric parameters