ABSTRACT
The purpose of the present study was to determine the effects of acetylation with different doses of acetic anhydride on the chemical composition and chosen functional properties of commercial pumpkin protein concentrate (PPC). The total protein content decreased as compared to unmodified samples. Electrophoretic analysis revealed that in the acetylated pumpkin protein, the content of the heaviest protein (35 kDa) decreased in line with increasing concentrations of modifying reagent. Acetylation of PPC caused a significant increase in water-binding and oil-absorption capacity and for emulsifying properties even at the dose of 0.4 mL/g. Additionally, an increase in foaming capacity was demonstrated for preparations obtained with 2.0 mL/g of acetic anhydride, whereas acetylation with 0.4 and 1.0 mL/g caused a decrease in protein solubility as compared to native PPC.
Subject(s)
Cucurbita/chemistry , Plant Proteins, Dietary/chemistry , Acetic Anhydrides , Acetylation , Amino Acids/analysis , Chemical Phenomena , Computer Simulation , Digestion , Electrophoresis, Polyacrylamide Gel , Emulsions/chemistry , Food Handling/methods , Humans , Seeds/chemistry , SolubilityABSTRACT
Starch modification by chemical reaction is widely used to improve the properties of native starch. Modified by citric acid, starch is characterized by specific properties resulting from the presence of citrate residues and as a result of cross-linking starch. The chemicals used for preparing starch citrates are safe for human health and the natural environment compared to the harsh chemicals used for conventional modifications. Starch citrates are traditionally produced by heating starch-citric acid mixtures in semi-dry conditions or by a heat moisture treatment. The conditions of the modification process (roasting temperature, heating time, citric acid dose) and the botanic source or genotype of starch determine the degree of substitution and the properties of the obtained preparations. Changes of starch properties occurring during esterification lead to reduced relative crystallinity, resulting in a decrease in the affinity for water, the gelatinization parameters, and the viscosity of starch citrate. However, one of the most important outcome of the modification is the formation of resistant starch (RS), which has increased resistance to the action of amylolytic enzymes. Currently, new methods for producing starch citrates with improved functional and rheological properties while maintaining the highest possible content of resistant starch are being sought. The article presents an overview of recent studies on the production, properties. And applicability of starch citrates with special attention paid to their role as preparations of resistant starch (RS). The use of citric acid for modification of starch is better for the technology process, while using cross-linking is better than simply using esterification.
ABSTRACT
Potato pulp is a nuisance waste from the production of potato starch, containing large amounts of dietary fiber; therefore, addition of the pulp to food may have a positive effect on the nutritional value of food products. To increase the amount of dietary fiber, shortcrust pastry cookies were baked by replacing some of the flour (20-100%) with an equivalent amount of dried potato pulp. In all the tested variants, correct confectionery products were obtained. The color of finished product (measured using Konica-Minolta CM-5 spectrophotometer) and mechanical properties of raw dough and baked cookies (subjected to a tensile test, using INSTRON 5544 Tensile Tester) were determined. Furthermore, the samples were subjected to sensory consumer assessment (evaluated on a 7-point hedonic scale). Colorimetric tests of the cookies showed a slight shift in their color from yellow toward green but at the same time lowering its saturation. Strength tests show that only the replacement of more than 40% of flour by the dried pulp resulted in a significant increase in the hardness of baked products. Regarding the tests with consumers, cookies containing up to 40% potato pulp were acceptable. Such a large addition of potato pulp to shortcrust pastry cookies creates new opportunities for this waste management.
ABSTRACT
Coloured-fleshed potatoes of four varieties were used as raw material for coloured flour and fried snack production. The effects of thermal processes traditionally used in dried potato processing and in snack pellet manufacturing on anthocyanin profiles, total polyphenols and antioxidant properties of obtained half- and ready products were studied. There was a significant influence of potato variety on the experimental flour and snack properties. Flours with the highest antioxidant activities were obtained from Salad Blue and Herbie 26 potatoes; however, the flour prepared from the Blue Congo exhibited a much higher total polyphenol and anthocyanin content. Snacks produced with coloured flour had 2-3 times higher antioxidant activities, 40% higher contents of polyphenols, attractive colour and better expansion compared to control samples. The lowest losses of anthocyanins during snack processing were in snacks with flour from the purple-fleshed Blue Congo and red-fleshed Herbie 26.
