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BACKGROUND: Gels of potato starches with varying amylose content were prepared and the degree of pasting and the course of retrogradation were studied. The average molar masses of granular and pasted starches were estimated. Determination of the degree of pasting involved use of optical microscopy and the study of pasting characteristics. The studies of susceptibility to retrogradation considered mechanical spectra, hardness, syneresis, resistant starch content, and X-ray measurements. RESULTS: Heating of the starch suspensions at 95 ∘ C resulted in almost complete deterioration of granules. Changes in storage modulus (G') exceeded these of loss modulus (G"). Values of G' and G", hardness and syneresis increased with the period of the sample storage and, simultaneously, the relevant tangent of the phase shift angle (tg (G"/G')) decreased. A tendency was observed for the resistant starch (RS) content to increase on prolonged storage of gels. The patterns of diffractograms for the pasted and lyophilized samples only differed slightly. CONCLUSION:The pastes of all the studied potato starches were characterized by a similar degree of pasting. The most essential changes in the physicochemical properties of the gels were observed between the 30th and 90th days of storage. The susceptibility of potato starch gels to retrogradation, especially within the first 2 h, was controlled, mainly by the amylose content.Resistant starch (RS) content. Samples containing 50 g kg −1 (m/m) starch were prepared following the method described in the section on texture, above. Directly after preparation, 45 cm 3 of the pastes were poured into 60 cm 3 polypropylene containers wileyonlinelibrary.com/jsfa J Sci Food Agric 2019; 99: 2393-2403 TextureThe hardness of all the samples investigated, after 1 and 2 h, was comparable (Fig. 3). An increase in hardness of the gels could be observed after the first day and then between the 30th and 90th days. This confirmed two-step, short-and long-term J Sci Food Agric 2019; 99: 2393-2403

The aim of this study was to examine the effect of sourdough addition to partially baked and frozen (PBF) wheat rolls on the glycemic index (GI). The study was performed on healthy humans (n = 15). The volunteers were asked to attend six times in the early morning, over 3 weeks. Each human tested four types of wheat rolls – two without sourdough addition: (i) fully baked, non‐frozen (FBNF); (ii) PBF; and two with the addition of 3% dehydrated sourdough: (iii) FBNF (FBNF + S), (iv) PBF (PBF + S). Glucose solution was used as a reference food and tested twice. Blood glucose concentrations were measured before consumption, as well as at 15, 30, 45, 60, 90, and 120 min after the start of the meal. In the study, the addition of 3% dehydrated sourdough to fresh and frozen wheat rolls resulted in a significant decrease in the glycemic response, by 24% – FBNF + S (GI = 63 ± 7) and PBF + S (GI = 43 ± 4) – compared to the samples without sourdough: FBNF (GI = 87 ± 11), PBF (GI = 67 ± 3) (p ≤ 0.05). Both factors (freezing and sourdough), applied to the wheat rolls at the same time, statistically significantly reduced the GI, by 44% (p ≤ 0.05). The results of the study show that sourdough supplementation separately and sourdough supplementation combined with frozen storage of white wheat rolls have a significant impact on the glycemic response.

Plant-based foods should be fresh, safe, and natural, with nutritional value and processed in sustainable ways. Among all consumed vegetables, Brassica vegetables are considered to be the most important ones. As they are eaten in large quantities and frequently, they may constitute an important source of nutrients and bioactive compounds in a daily diet. This work is aimed at assessing the effect of technological processing (blanching and traditional cooking in water and in a convection steam oven) as well as the method of frozen storage (in PE-LD zipper bags and vacuum packing) on the content of selected components in purple cauliflower. The material was examined for the content of dry matter, vitamin C, total polyphenols, anthocyanins, thiocyanates, nitrates, and nitrites, as well as antioxidant activity. All technological processes caused significant changes in the contents of examined nutritive and non-nutritive compounds as well as in antioxidant activity or the level of selected chemical pollutions. A trend was also observed towards lower constituents’ losses as a result of convection steaming, compared to traditional cooking in water. Moreover, the reduction in the content of examined compounds was smaller in vacuum-packed and frozen-stored vegetables then in those stored in zipper PE-LD bags.

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