Fruit growing
and viticulture of South Russia
Abakumova Alla
Articles in journal: (total 8)
After processing of grapes there is a huge amount of waste, including about 20-30% of grape pomace, which must be involved in further turnover. Grape pomace consists mainly of the skin, seeds, ridges and remaining pulp, the processing of which will partially to solve both environmental and economic issues related to the involvement of pomace in the technological process of production of new products. The grape berry contains such organic acids as malic, citric, amber, oxalic, lactic and others, the study of which is also of scientific and practical interest. The composition of organic acids of sweet pomace from grape varieties: Chardonnay, Pinot Blanc, Riesling, Sauvignon Blanc, Traminer, Pinot Noir, as well as fermented: Merlot, Saperavi. Pomaces are selected at the enterprises of the Krasnodar region is studied in this work. Studies of organic acids were carried out in water-alcohol extracts. First, the pomace was extracted with hot water (70 ℃), and then with ethyl alcohol of 96.5 % vol., that made it possible to extract more fully the organic acids. Comparison of organic acids content in the samples was carried out after conversion to dry matter. It was revealed that the main acids of grape pomace are tartaric and malic acids. Concentrations of tartaric acid varied from 20.30 g/kg to 70.99 g/kg, malic acid from 4.75 to 19.40 g/kg. The grape variety, the conditions of its processing, the place of grape growing had a significant impact the concentration of both total and individual organic acids.
The influence of grape dietary fibers on decontamination of natamycin in wine has been studied. Grape dietary fibers obtained from sweet pomace of Chardonnay grapes and fermented grapes Krasnostop Anapskiy, Cabernet Sauvignon and Merlo were used for the studies. The mass fraction of fiber in the presented fiber samples ranged from 57.2 2.9 (Cabernet Sauvignon) to 65.3 3.3 % (Chardonnay), the electrokinetic potential from minus 26 3 (Chardonnay) to minus 49 5 mV (Krasnostop Anapskiy). Studies were carried out on a model mixture of dry white wine with 10 mg/dm3 of introduced natamycin. Influence of time of contact of wine with fibers and their amount on sorption of natamycin was established. It was revealed that the maximum sorption of natamycin occurs when in contact with fibers during the first 2 hours, so further maintenance of them is impractical. The addition of the fibers to the wine in an amount of 3.0 g/dm3 resulted in the removal of natamycin from 42 to 68 %. Fibers obtained from white Chardonnay grape pomace contributed to less sorption of natamycin, and from red pom-ace of Krasnostop Anapskiy grape variety more, which correlates with values of electrokinetic potential on the surface of the fibers. It is assumed that for the complete decontamination of natamycin it is necessary to use combined treatments with other sorbents having a negative charge of active centers on the surface.
New knowledge was obtained about the conformity to natural lows of changes in physicochemical and organoleptic indicators of wine production in the presence of a preservation of microbial origin of nisin (food supplement E234), which will become the basis for the technological foundation of additional processing of sorbents for wine materials aimed to increasing in their consumer safety and quality. It was established in the process of research that in the experimental samples of wine with the addition of nisin all analyzed parameters ( volume fraction of ethyl alcohol, mass concentration of sugars, mass concentration of titrated acids in terms of tartaric acid, mass concentration of volatile acids in terms of acetic acid, mass concentration of the above extract, mass concentration of citric acid, mass concentration of total sulfur dioxide, organic acids, phenolic compounds, including anthocyanins for red wines) the physical-chemical composition of the test samples of wines remained unchanged, and remained at the same level as in the control samples. Study carried out of white and red wines with the addition of nisin showed that during the aging the typical oxidation-reduction processes are occurred typical to the wine aging process. The most significant was the change in the mass concentration of organic acids, which mainly affects the taste and, consequently, the quality of the wine. As a result of the analysis of experimental data, it was established that the control and testing samples had the same organoleptic characteristics and tasting score. Dry white table wine has a straw color, pure wine aroma with flower shades, corresponding to wine type; full harmonious fresh taste, without extraneous shades.