La Cava E.L.M.,Laboratorio Of Tecnologia Quimica Y Bromatologia |
Sgroppo S.C.,Laboratorio Of Tecnologia Quimica Y Bromatologia
LWT - Food Science and Technology | Year: 2015
The effect of the UV-C light (doses: 0.0-3.94J/cm2) on the main bioactive compounds of grapefruit juice and their stability were evaluated throughout 30 and 16 days of storage at 4 and 10°C respectively. Organic acids (citric, malic, ascorbic and tartaric) and flavonoids (naringin, hesperidin and neohesperidin) were quantified by HPLC, whereas total phenols and the antioxidant capacity were determined by spectrophotometric methods. The UV-C treatments caused a significant decrease (15%-30%) in ascorbic acid and antioxidant capacity (10%-27%), which was related to the applied dose. However, no changes (p>0.05) in others organics acids, individual flavonoids, total phenols, pH, °Brix, color and titratable acidity were observed after UV-C treatment. During the storage at both temperatures, a decrease in the neohesperidin levels (43%-53%) was detected whereas the others parameters analyzed did not show changes (p>0.05). The microbiological quality of grapefruit juices treated with 3.94J/cm2 was maintained for 15 and 10 days at 4 and 10°C respectively. © 2015 Elsevier Ltd.
Ojeda G.A.,Laboratorio Of Tecnologia Quimica Y Bromatologia |
Sgroppo S.C.,Laboratorio Of Tecnologia Quimica Y Bromatologia |
International Journal of Food Science and Technology | Year: 2014
Summary: To control browning phenomenon, an edible coating of cassava starch along with ascorbic acid (AA) (combined treatment) was applied to minimally processed sweet potatoes var cv. 'Blanca Correntina'. The samples were stored at 4 °C for 16 days, and the activities of polyphenol oxidase, peroxidase and phenylalanine ammonia lyase were studied; also, surface colour, antioxidant capacity, ascorbic acid, chlorogenic acid content were evaluated. The combined treatment showed a beneficial impact on the quality of the product, avoiding browning when compared with untreated samples and individual treatments (coating without AA or immersion in AA solution). The improvements were evidenced by the absence of changes in hue, minor changes in a* parameter and a major inhibitory effect of AA on the activity of the three enzymes. Ascorbic acid content and antioxidant capacity increased (P < 0.05). The combined treatment not only was effective in preventing enzymatic browning but also retained freshness and improved nutritional value. © 2013 Institute of Food Science and Technology.