EVALUATION OF JUICES PRODUCED FROM TWO VARIETIES OF SEEDLESS GRAPES | ||||
| Egyptian Journal of Agricultural Research | ||||
| Article 22, Volume 82, Issue 4, December 2004, Page 1761-1773 PDF (3.86 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ejar.2004.275376 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| LOBNA A.M. HAREEDY1; ATYA EL-MAKHZANGY2; EL-SAYED ABDEL-LATIF1 | ||||
| 1Food Technology Research Institute, Agricultural Research Center, Giza, Egypt | ||||
| 2Agro-Industry Department, Institute of Efficient productivity, Zagazig University, Egypt | ||||
| Abstract | ||||
| The extracted juice of two different seedless grapes cultivars Flame (F) and Early Superior (ES) recently imported to Egypt were used in this study. The juice of these varieties was not preferable to the Egyptian consumer, due to its high sour taste and color degradation. Therefore, studies were carried out to overcome this problem through preparing suitable blends of the two juices. Pectic enzymes were added to the crushed berries before juice extraction in order to increase the juice yield, T.S.S, total sugars, total acidity and the coloring agents (total anthocyanin). Sensory evaluation indicated the low acceptability of each juice, hence the Flame juice was blended with the Early superior at the ratios of (3:1, 1:1, and 1:3, respectively). Results confirmed that the blend ratio 1 : 1 was the most palatable and more preferable by the panelists. Some chemical additives such as (Potassium sorbate, Calcium lactate, Ascorbic add, Sodium meta bisulphlte) were added to the blends either separately or in combination with each other in order to find their effects on the blend qualities especially during storage at 5°C for 6 months. Results indicated that the best treatment was that for the blend 1 : 1 containing 0.05% ascorbic add plus 80 ppm sodium metabisulphite and 0.1% potassium sorbate stored at the same conditions. Besides, the interaction between the additives and the storage period showed no significant effect on the sensory properties. Correlation coeffident between sensory and chemical qualities were also studied. Economic study was carried out for the grape juice production. Moreover, pasteurization at 85°C for 5 minutes and the addition of 80 ppm sodium metabisulphite (treatment No. 5, 6 and 7) were sufficient to prevent microbial spoilage of the juice during 6 months storage at 5°C. | ||||
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