This study examined the quality characteristics of jelly prepared with green grape juice (GJ). The pH, oBrix value, color, texture, and sensory evaluation of the jelly were measured. The pH of the jelly significantly decreased with increasing amount of GJ over the range of 3.25-5.27. The oBrix value of the jelly showed a significantly higher result as the amount of GJ increased (p<0.001). Lightness (L) and redness (a) decreased with increasing amount of GJ, and yellowness (b) increased. In the texture measurement, the GJ-100 sample group with a high substitute rate of GJ showed high hardness, gumminess, and chewiness (p<0.001). The results of principal component analysis (PCA) showed that the sample groups with high GJ content were classified as having relatively strong yellowness, sweet aroma, metallic aroma, grassy aroma, sweetness, sourness, green grape skin taste, and astringency. In the acceptance test, the GJ-50 sample group was evaluated to be high in flavor (p<0.001) and overall acceptance (p<0.01). However, sample groups consisting of 50% or more GJ were evaluated to be significantly strong in terms of astringency. Therefore, further study needs to be conducted about improving astringency in the future.
This study was done to develop the standard recipe for nutritious cowpea starch based grape jelly. The effects of grape juice concentration (4, 8, 12%) and 0.2% calcium addition were evaluated on textural and sensory properties of grape jelly through the instrumental analysis using rheometer and sensory evaluation. Instrumental analysis showed that hardness, chewiness and gumminess of grape jelly was incerased significantly In jelly made of higher concentration of grape juice, and also in 0.2% calcium containing jelly. According to sensory evaluation, higher grape juice contains jelly showed advantages in preference of color and overall quality. Calcium addition increased sourness in sensory score. Overall, 12% grape juice and 0.2% calcium containing jelly was most preferable, which means calcium fortified cowpea starch based grape jelly was successful try for nutritious and practical food for elementary school foodservice.