Qualities changing during storage
The qualities changing of cracker wereinvestigated of aw, hardness, color and sensory evaluation for twelve weeks. At first date of storage, aw was 0.41 and trended to increase slightly (Figure 2) until three months. Water activity range was 0.39-0.53 and it was in scope which was set as 0.55. Hardness of cracker at initial week was 301.24 and increased to 416.24 g force at twelfth week (Figure 3). The changing of lightness was nearly constant with range of 31.70-35.13. Redness increased from 7.06 to 10.70 alike the yellowness, it increased from 4.90 to 7.20 within three months (Figure 4).
The sensory evaluation (Table 4) was found that hedonic score of color, size crispy, Panang flavor, taste and overall liking were in range of 6.5-8.0. It could be explained that panelist like cracker slightly to like very much. During twelve weeks of storage, all attributes had higher score than borderline as 6.5 and acceptance of product was 93.33%. Hence, it could be say that shelf life of black glutinous rice crackers was twelve weeks at least.