Quality parameters of fermented kvass extract

Abstract

The aim of this research was to compare the commercially available kvass concentrate to the kvass extract which was experimentally produced from the naturally fermented kvass. Dry matter was determined according to the standard ISO 2173:2003, active acidity-ISO 10523:2012, and apparent viscosity was measured with a DV-III Ultra Brookfield rheometer, using a spindle SC4-18 with the speed 50 rpm at 26.9 °C. Sugars were determined using high-performance liquid chromatography. The sensory evaluation of kvass drinks (recombined kvass concentrate and extract) was performed according to the ISO 4121:2003. The dry matter content in the kvass concentrate (Ltd. Ilgzeem) was 69 %; it was diluted with distilled water to the dry matter content 32.4 ± 0.2 % of kvass extract (made from Ltd. Liepzeme kvass). Active acidity in the kvass concentrate was significantly (p = 0.012) lower (pH 2.86) than in the kvass extract (pH 4.18). Apparent viscosity in the kvass extract was 13.68 mPas and in the kvass concentrate 5.22 mPas. Major sugars in the kvass extract were fructose and glucose and in the commercial kvass concentratefructose. Hedonic evaluation showed that there were no significant differences (p > 0.05) in the preference of kvass drinks. The intensity of aroma, flavour and acidity was significantly more pronounced in the kvass drink made from the commercial kvass concentrate.

Comparison of the Antioxidant and Sensorial Properties of Kvass Produced from Mountain Rye Bread with the Addition of Selected Plant Raw Materials

“…In the studies of other recipe variants of kvasses (Table 4), including the participation of peppermint infusion, higher values of the particular parameter were recorded in the range of pH = 4.2-4.6. Similar results were obtained by other authors [11][12][13] in studies of kvass based on rye bread, which confirms that the mountain rye bread used in the discussed studies is also a good raw material for obtaining water extract for fermentation into kvass.…”

“…As can be seen from a comparison of the results of other authors' studies, the alcohol content of a finished product such as kvass depends on the recipe and the conditions for making the kvass. Of particular importance is the proportion of sugar and the composition of the microflora [11][12][13]18].…”

“…Kvass contains no greater than 1.5% alcohol by volume, while with longer stands, the alcohol concentration can reach 2.5% or more. Unlike other grain-based alcoholic beverages, kvass is considered a non-alcoholic beverage [2,[11][12][13][14]. Kvass is a refreshing beverage with a pleasant aroma of rye bread and a moderately sweet and sour taste, which is most in demand during hot weather on summer days [15][16][17].…”

A comprehensive review on functional beverages from cereal grains-characterization of nutraceutical potential, processing technologies and product types

“…Rye flour and rye malt are commonly used to make commercial kvass after they have been cooked with water. Prior to fermentation, these ingredients are combined and also subjected to saccharification (by malt enzymes) [ 47 ]. Kvass is regarded as a non-alcoholic beverage even though it may have trace amounts of alcohol (less than 1.5%); if the alcohol content rises above that point, the kvass is deemed spoilt (Xiong et al, 2020).…”