No abstract

The research aimed to study the effects of 0-20% substitution of wheat flour with grape pomace powder (GPP) on the rheological and pasting properties of wheat dough, and on sensory properties, digestive and antioxidant activities of the prepared biscuits. The results of rheological analysis showed that incorporation with GPP concluded in reduced water absorption (WA) and increased dough stability. Rapid visco-analyser (RVA) results suggested GPP could increase the breakdown value of the starch paste system but decrease the setback and peak viscosity. With respect to biscuit properties, it was found that 5%-15% GPP resulted in increased chewiness and hardness of biscuits. Also, it was recorded that GPP significantly improved antioxidant activity and DPPH and hydroxyl radical scavenging capabilities. Although the in vitro digestibility results showed that the addition of GPP displayed minor influence on digestion rate, the sensory analysis results showed that the biscuits supplemented with GPP to a level of 10% resulted in products with good overall acceptability. Additionally, biscuits incorporated with an addition amount of 10% GPP exhibited nailing oxidation resistance and can be considered as a food with a high fiber content, which is a good option for people to pursue modern healthy foods.

Substantiation of the expedience of using of natural antioxidants for inhibiting of oxidative and hydrolytic rancidity in confectionary products is an urgent direction. The offered way of solving the problem is to use a defatted grape seed powder, a product, obtained as wastes of vine-making as a source of antioxidants. For this aim, there were realized experimental studies of water-alcohol extracts (ethanol, isopropanol) by the method of gas chromatography with mass-spectroscopic detection (CG-MS) of the chemical composition of grape seed powders under industrial conditions. The obtained data allowed to establish that the studied extracts contain an essential amount of phenol compounds of the different origin: aromatic acids-gallic and egallic acids; resveratrol; flavonoids-quercetin and its derivatives, catechine, epicatechine, campferol and others alongside with esters of fatty acids. These components are strong antioxidants, and their introduction to a grape seed powder must favor inhibition of the oxidizing process of fats in fat-containing confectionary products, so increasing shelf-life of products.

Grape seed powder (GSP), grape skin powder (GSKP), or grape pomace powder (GPP) was introduced as partial substitution for wheat flour (WF) with variable percentages by weight (0-20 wt%), and the resultant addition effects on the rheological and microstructural properties were studied. GPP and GSP significantly (p < .05) reduced the water absorption but three types of grape powders could increase the development time and dough stability. Furthermore, all kinds of grape powders with various incorporations could significantly (p < .05) enhance the strength of dough systems. Grape powders decreased the storage (G′) and loss (G″) moduli, while the tan δ increased with the increasing of GSP/GSKP/GPP addition levels. The microstructure observation of composite doughs suggested that the integrity and continuity of gluten networks were destroyed in the presence of grape powders. Based on the above results, the GSP addition levels of 10% to 15%, GSKP/GPP of 5% to 10% are recommended. Influencia de la adición de polvo de orujo de vino Cabernet Sauvignon en las propiedades reológicas y microestructurales de la masa de trigo RESUMENEn el presente estudio se introdujo polvo de semilla de uva (GSP), polvo de piel de uva (GSKP), o polvo de orujo de uva (GPP), para sustituir parcialmente la harina de trigo (WF) en porcentajes variables en peso (0-20%), estudiándose los efectos resultantes de dicha adición en las propiedades reológicas y microestructurales. Aunque el GPP y el GSP redujeron significativamente (p<.05) la absorción de agua, los tres tipos de polvo de uva aumentaron el tiempo de desarrollo y la estabilidad de la masa. Además, todos los tipos de polvo de uva adicionados en cantidades diversas mejoraron significativamente (p<.05) la resistencia de los sistemas de masa. Asimismo, los polvos de uva disminuyeron los módulos de almacenamiento (G′) y de pérdida (G″), mientras que con el incremento de los niveles de adición de GSP/GSKP/GPP se produjo el aumento del tan δ. La observación de la microestructura de las masas compuestas permitió constatar que, en presencia de los polvos de uva, se destruyeron tanto la integridad como la continuidad de las redes de gluten. Los resultados anteriores llevan a recomendar niveles de adición de GSP de 10% a 15%, y de GSKP/ GPP de 5% a 10%.

The effect of grape powders on the rheological properties of dough and the indicators of butter biscuits quality have been investigated. Butter biscuits were cooked with the addition of powdered grape seeds and grape skins from the grape pomace obtained in the southern regions of Ukraine. The grape powders were added to the dough in an amount of 15.0% of the weight of the wheat flour. It has been shown that the presence of powdered grape skins increases the dough’s effective viscosity by 3.9 times, of powdered grape seeds – by 5.4 times, as compared to the reference sample, and it makes the dough more resistant to destruction. Adding powdered grape skins increases the plastic viscosity of the samples by 31.4%, powdered grape seeds – by 38.1%. The higher plastic properties of the dough allow the biscuits to hold their shape better and to retain the pattern on their surface. With grape powders added, the adhesive strength of the dough decreases. When powdered grape skins are added, the adhesion strength decreases by 23.0 %, and if we add powdered grape seeds, by 33.0%. It facilitates the work of moulding equipment and reduces the production losses of the dough during processing and moulding. The values of physicochemical parameters of the quality of butter biscuits – the specific volume and the wetting ability – slightly increase as compared to the reference sample. Products hold their shape better, and do not become runny during baking, because of a higher degree of form stability. Organoleptic indicators of the quality of butter biscuits with experimental additives are becoming better. Biscuits acquire a pleasant nutty taste after adding powdered grape seeds, and the taste and flavour of prunes and raisins after adding powdered grape skins. Butter biscuits take a deep chocolate colour or chocolate with a violet tint.