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  • Author or Editor: S. Joshi x
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Lactic acid fermentation of carrot as a method of preservation using different lactic acid bacteria, viz. Lactobacillus plantarum, Pediococcus cerevisiae and Streptococcus lactis subsp. diacetylactis as such and in sequence at different temperatures and with varying salt content (2, 2.5 and 3%) were employed in the fermentation of carrot. The differences in fermentation behaviour of different microorganisms were quite contrasting at 26 °C, but the sequential culture started deviating from the very first day and acidity increased up to 6 days. A temperature of 26 °C and salt concentration of 2.5% were the best for lactic acid bacteria (LAB) fermentation of Asiatic carrot as highest acidity (1.40% lactic acid), low pH and low reducing sugars were achieved in sequential fermentation. The LAB count of 7.8×10 8 CFU ml −1 was also higher at these concentrations coupled with higher sensory scores of the products. Among the fermentation types tried, sequential culture fermentation of the vegetables produced the product with higher acidity, low pH and reducing sugars. The sequential culture fermentation imparted the fermented products better flavour, texture and taste than other products fermented naturally or with lactic cultures of Pediococcus cerevisiae, Lactobacillus plantarum and Streptococcus lactis in single separate fermentation. Based on the overall and sensory quality evaluation, the fermented carrot product prepared with sequential culture was the best followed by the product prepared using natural microflora.

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Strawberry fruits of three cultivars viz. Camarosa, Chandler and Doughlas were used to prepare wine by four different methods (control, thermovinification, fermented on the skin and carbonic maceration). Physico-chemical characteristics of the cultivar Camarosa were rated superior to Chandler and Doughlas. The must from the fruits fermented on the skin gave the highest rate of fermentation and ethanol content. The application of various treatments improved the fermentation behaviour of treated strawberry musts compared to the control as revealed by their physico-chemical characteristics. Thermovinified wines had many desirable characteristics such as more total phenols, esters and colour with comparable amount of higher alcohols, volatile acids, ethyl alcohol, sugars and anthocyanin. The carbonic maceration resulted in wines with more alcohol, higher pH, lower acidity, lesser higher alcohol and volatile acids than other wines. Fermented on the skin treated wines were typical for higher amount of anthocyanin, lower reducing sugar and total sugar than the control wines. Thermovinified wines, irrespective of cultivars, scored the highest with respect to most of the sensory quality characteristics. Wines from Camarosa cultivar registered many desirable characteristics such as esters, optimum acidity, more red colour units with comparable contents of alcohol and total phenols, while Chandler cultivar had higher amount of ethyl alcohol, more phenols, anthocyanin than other cultivars. Some of these differences are correlated with their initial characteristics, while others have been influenced by method of vinification. Based on the physico-chemical and sensory qualities, the wines from cv. Camarosa was rated the best, though the wines of all the cultivars were acceptable.

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Flavour profiling by descriptive analysis of apple wines fermented with different Saccharomyces cerevisiae strains and natural sources of fermentation with or without nitrogen source addition was carried out. Out of 45 attributes used, 38 were found significant and were employed for further evaluation. Generally, the intensities of many of the descriptors in the apple wines were low. Both the natural sources of fermentation (NSF) imparted different flavours notes like lactic, sharp, acetic and fruity to the wine. “W” strain of Saccharomyces cerevisiae gave wines with higher astringency and phenolic flavours, ethyl acetate like, acetaldehyde like flavour, UCD 505 and UCD 522 fermentated wines were peculiar for more ethanolic, sweety and bitter taste, whereas UCD 595 imparted more phenolic, astringent, sour, and ethanolic flavour notes to the wines. The addition of nitrogen source (irrespective of source of fermentation) reduced the development of some flavours considered undesirable (acetic, amyl alcoholic, fusel alcoholic, vegetative). Addition of nitrogen source enhanced the intensity of some other flavour attributes like ethanolic and phenolic in the wines. Due to the same vinification practices (except for the source of fermentation) some modifications in the flavour attributes of apple wines fermented by natural source of fermentation were recorded. The flavour profile of wines fermented by different sources of fermentation, was also reflected in the chemical characteristics examined. Besides higher fermentability, the addition of nitrogen source also affected the physico-chemical characteristics of the wines and consequently, their flavour profile. Application of Principal Component Analysis (PCA) to the means of flavour scores generated from flavour profiling, weakly separated and characterized the wines fermented by different sources of fermentation but did not differentiate the wines fermented with or without nitrogen source. It is concluded that the descriptors described here can characterize apple wine of different quality attributes. The list of descriptors, concentration of standards and details of the technique have also been described.

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