ISHS Acta Horticulturae 438: III International Congress on Cactus Pear and Cochineal
INFLUENCE OF PH AND CONTENT OF CARRAGEENAN DURING THE STORAGE OF CACTUS PEAR GELS |
| Authors: | C. Sáenz, S. Arriagada, S.M. Fiszman, C. Calvo |
| Keywords: | prickly pear, Opuntia ficus-indica, thickening agents, jelly |
| Abstract:
Different formulations of cactus pear gels had been tested using two pH levels (3.5 and 6.1), two different quantities of saccharose (35 and 40%) and two proportions of carrageenan (0.6 and 0.9%). Two formulations were chosen out from the eight under study (F1 : 58.8% pulp, 40% saccharose, 0.6% carrageenan, pH 3.5 and F2: 58.5 % pulp, 40% saccharose, 0.9% carrageenan and pH 6.1) and its stability had been evaluated during 4 weeks, at 5 – 6°C. The green gels colour was initially different, the 6.1 pH gel presented a significatively lower a* value than the 3.5 pH gel (-2.1 and -1.2 respectively). The colour from the two selected gels remained practically constant during the storage, since the changes of L* values were small, although significatives for 6.1 gel. The L* value of the 3.5 pH gel changed from 28.6 to 29.3; the one with pH 6.1, varied from 28.6 to 27.0. The hue (H*) changed from 101° to 105° in the 3.5 pH gel and in the 6.1 pH gel changes slightly and recovers the initial value at four weeks storage. The equation that established the light darkness observed in the 6.1 pH gel was y = 28.23–0.05x (x is time and y is L*). A lower drop in syneresis values of the 6.1 pH gel was observed during the storage, as compared to the 3.5 pH gel, which presented the opposite tendency (1.77 to 2.24 mm). The influence of pH was evident in the microbiological quality, since the quantities of fungi and yeast were significatively lower in the 3.5 pH gel than those of the 6.1 gel. | |
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