Physicochemical Characteristics of Loaf Bread Added with Waxy Black Rice Flour by Storage Period

찰흑미분 첨가 식빵의 저장기간별 이화학적 특성 변화

To analyze die quality characteristics of loaf bread added with waxy black rice flour by its storage period, this study stored loaf bread made of wheat flour added with 10% 20% 30% and 40% of waxy black rice flour for 4 days while measuring water activity, pH, chromaticity and texture. The results of die study are as follows. Based on die results of measurements of water activity of loaf bread added with waxy black rice flour by storage period, die control group and die groups added with 10% and 20% of waxy black rice flour showed significantly low water activity from the $3_{rd}$ day of storage and die groups added with 30% and 40% of waxy black rice flour from the $2_{nd}$ day of storage. As for pH changes over the storage period, only die group added with 40% of waxy black rice flour showed significant pH decreases from die $3_{rd}$ day of storage while the control group and the groups added with 10% and 30% of waxy black rice flour showed significant pH decreases from die $2_{nd}$day of storage. As for the pH of each group of loaf bread by storage days, die loaf bread added with 40% of waxy black rice flour showed significantly higher pH compared to the control group. Brightness decreased significantly from the 2nd day of storage and die yellowness from the $3_{rd}$ day of storage. As for chromaticity changes by storage days, as die amount of added waxy black rice flour increased, L values and b values decreased while redness values significantly increased. Over die storage period, hardness, gumminess and chewiness increased and die waxy black rice flour added groups showed lower increase rates compared to die control group. Especially, die groups added with 30% and 40% of waxy black rice flour showed low hardness changes. Springiness level was decreased as die addition rate of waxy black rice flour was increased, and the group added with 40% of waxy balck rice flour showed die lowest springiness level. It also showed lower cohesiveness up to the 3rd day of storage compared to die day of manufacturing. Therefore, it could be seen that die loaf bread made from wheat flour added with 30% of waxy black rice flour showed better quality feature until die $3_{rd}$ day of storage than die other experimental groups.

찰흑미분을 첨가한 식빵의 저장기간별 품질특성을 분석하기 위하여 본 연구에서는 찰흑미분을 밀가루에 10%, 20%, 30%, 40% 첨가하여 제조한 식빵을 4일간 저장하며 수분활성도, pH, 색도, 텍스쳐를 측정하였고 그 결과는 다음과 같다. 찰흑미분 첨가 식빵의 저장기간에 의한 수분활성도 측정결과를 기초로 했을 때, 대조군과 찰흑미분을 10%, 20% 첨가한 군은 저장 3일째부터, 찰흑미분 30%와 40%를 첨가한 군은 저장 2일째부터 유의적으로 낮은 수분 활성도를 보였다. 저장기간 동안의 pH의 변화에 대해서는 찰혹미분 40% 첨가군만이 저장 3일째부터 유의적인 pH 감소를 보인 반면 대조군, 10%, 30% 첨가군은 저장 2일째부터 유의적인 pH 감소를 보였다. 저장일에 의한 각 식빵군의 pH에 대해서는 찰흑미분 40% 첨가 식빵이 대조군에 비해 유의적으로 높은 pH를 보였다. 저장일에 따른 색도변화를 살펴보면 명도는 저장 2일째부터, 황색도는 저장 3일째부터 유의적으로 감소하였다. 찰흑미분 첨가량이 증가함에 따라 L값과 b값은 감소한 반면 적색도 값은 유의적으로 증가하였다. 저장기간 동안 경도, 검성, 씹힘성은 증가하였고, 찰흑미분 첨가군은 대조군에 비해 낮은 증가율을 보였다. 특히 찰흑미분 30%와 40% 첨가군이 낮은 경도변화를 보였고, 탄력성에 대해서는 찰흑미분 첨가율이 증가함에 따라 탄력성이 감소되어 40% 첨가군이 가장 낮은 탄력성을 보였다. 찰흑미분 40% 첨가군은 저장 3일 까지는 제조당일에 비해 더 낮은 응집성을 보였다. 따라서 찰흑미분 30%를 첨가한 식빵은 다른 실험군 보다 저장 3일까지 더 좋은 품질특성을 보인다고 할 수 있다.