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  • Author or Editor: K. Sandhu x
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The naturally fermented alcoholic (NFA) beverages collected from tribal areas contained higher quantity of methanol, with wide variations in ethanol, pH and volatile acidity. The NFA beverages were also found to be contaminated with Brettanomyces spp. and coliform bacteria indicating a potential danger of their consumption. The examination of natural sources of fermentation (NSF), frequently used in such fermentations, revealed the presence of fungi viz., Aspergillus flavus, Aspergillus oryzae, Mucor spp., Rhizopus spp.: the yeast included Saccharomyces spp., Scytalidium thermophilus (Torula) and Rhodotorula and bacteria viz., Pediococcus, Leuconostoc and Pseudomonas. Except for a few, the general ethanol productivity of the isolates from NSF was low. Saccharomyces spp. had higher population and was predominant among the yeasts isolated from NSF. The abnormal characteristics of the NFA beverages could be correlated with the raw materials, source and method of fermentation and distillation. Use of pure yeast and proper distillation method could improve the quality of such beverages.

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Vitreousness is an important quality characteristic that affects the yield of semolina during milling of durum wheat. It has been observed that kernel vitreousness seems to be lower when durum is exposed to damp conditions just before harvest. The main objective of this research was to determine the effect of high relative humidity (RH) on kernel vitreousness of ten durum wheat cultivars. Spikes were exposed to 88% RH at room temperature for 1 and 3 days. This resulted in increased spike moisture, kernel moisture and kernel size. Vitreous kernel content (vitreousness) decreased 23.6% after spikes were exposed to high relative humidity for 3 days. Exposure to 88% RH caused the greatest decline in vitreousness with the cultivar ‘Ben’.

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Abstract  

Uranyl ion is photochemically reduced to uranium(IV) in the presence of triethylamine and triethylamine is oxidized to secondary amine and acetaldehyde. On the basis of product analysis, temperature independent quantum yields for uranium(IV) formation and abnormal Stern-Volmer plots rule out the simple collisional photochemical annihilation of excited uranyl ion with triethylamine. Static annihilation has a significant contribution in addition to dynamic annihilation.

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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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Physicochemical, pasting, and rheological properties of pearl millet starches were studied and correlations among these properties were calculated. Amylose content, swelling power, and solubility of starches varied from 11.57 to 21.93%, 11.11 to 17.91 g g−1 and 12.20 to 15.20%, respectively. Volume% of starch granule size less than 10 µm varied from 36.23 to 48.34%, and 12.16 to 18.75% for above 20 µm size of granule. Peak viscosity of starches varied from 1291 to 1853 mPa·s, cv. RHB-173 had the highest value. Frequency sweep measurement of starch pastes revealed higher magnitude of G′ as compared to G″ with increase in to, indicating visco-elastic behaviour. Yield stress (σo), consistency index (K), and flow behaviour index (n) were observed as 40.73 to 115.72 Pa, 0.729 to 3.998 Pa·s, and 0.604 to 0.964, respectively. Starch pastes from cultivars studied showed shear thinning behaviour.

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