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Todi, Italy

Germani A.,University of Rome La Sapienza | Luneia R.,Analysis srl. | Nigro F.,University of Rome La Sapienza | Vitiello V.,University of Rome La Sapienza | And 2 more authors.
Annali di igiene : medicina preventiva e di comunità | Year: 2014

To analyze the yogurt amino acid profile starting from marketing through the whole shelf-life. The evaluation of the proteolytic activity of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus salivarius subsp. thermophilus, allows to deduce their vitality during the shelf-life period and within 45 days. Three types of full fats yogurts have been analyzed (a) natural white (b) sweet white and (c) whole fruit - in two stages: t0 (first day of shelf-life) and t1 (end of shelf-life). The proteins have been analyzed by the Kjeldahl method and the amino acid profile by HPLC. In natural yogurt a significant increase of the amount of free amino acids has been observed during the period of shelf-life (97%). In the sweetened full fats and fruit yogurt, instead, there is a lower increase of respectively 33% and 39% In whole milk natural yogurt, based on our data, the proteolytic activity seems to persist during the entire period of the shelf-life and this can be considered an index of bacterial survival, especially of Lactobacillus delbrueckii subsp. bulgaricus during the marketing process. Source

De Sanctis F.,Viterbo University | Silvestrini M.G.,Analysis srl. | Luneia R.,Analysis srl. | Botondi R.,Viterbo University | And 2 more authors.
Food Chemistry | Year: 2012

Wine white grape bunches of the Grechetto variety were dehydrated at 10, 20 and 30 °C, RH 45% and forced air ventilation of 1.5 m/s. Chemical and metabolic changes due to the effect of dehydration were studied at various stages of weight loss: 10%, 20%, 30% and 40%. Berry colour at 10 and 20 °C tended to become greener with dehydration but at 30 °C, at the final sampling, the colour darkened. Acidity decreased in all samples, while sugars increased. Total phenol content increased at 10 °C until 30% weight loss was reached and then declined, while at 20 and 30 °C the concentration decreased immediately. The contents of lutein and β-carotene (respectively 68 and 58 mg/kg d.w.), representing the 80% of total carotenoids, did not change significantly until the 30% of weight loss, when at 30 °C the value increased above all for lutein while at 10 and 20 °C, the contents decreased significantly. Daidzein, at 10 °C, rose significantly from about 150 μg/kg d.w. to 1434 μg/kg d.w. at 20% weight loss and then declined; at the same weight loss percentage, the genistein concentration began to increase. At 20 °C both isoflavones rose until the end of the experiment, reaching values similar to the sample at 10 °C. A temperature of 30 °C was deleterious to grape isoflavones. A discussion on the changes in isoflavones related to temperature and time is reported. © 2012 Elsevier Ltd. All rights reserved. Source

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