Purbaningrum Krisna, Hidayat Chusnul, Witasari Lucia Dhiantika, Utami Tyas
Department of Food and Agricultural Product Technology, Faculty of Agricultural Technology, Gadjah Mada University, Yogyakarta 55281, Indonesia.
Foods. 2023 Feb 14;12(4):820. doi: 10.3390/foods12040820.
Cocoa fermentation is an essential process that produces flavor precursors. However, many small farmers in Indonesia directly dry their cocoa beans without fermentation due to low yield and long fermentation time, resulting in fewer flavor precursors and cocoa flavor. Therefore, this study aimed to enhance the flavor precursors, particularly free amino acids and volatile compounds, of unfermented cocoa beans by hydrolysis, using bromelain. Unfermented cocoa beans were previously hydrolyzed with bromelain at concentrations of 3.5, 7, and 10.5 U/mL for 4, 6, and 8 h, respectively. An analysis of enzyme activity, degree of hydrolysis, free amino acids, reducing sugar, polyphenols, and volatile compounds was then conducted using unfermented and fermented cocoa beans as negative and positive controls, respectively. The results showed that the highest degree of hydrolysis was 42.95% at 10.5 U/mL for 6 h, although it was not significantly different from the hydrolysis at 3.5 U/mL for 8 h. This indicates a higher reducing sugar and lower polyphenols content than unfermented cocoa beans. There was also an increase in free amino acids, especially hydrophobic amino acids, such as phenylalanine, valine, leucine, alanine, and tyrosine, and desirable volatile compounds, such as pyrazines. Therefore, this suggests that hydrolysis with bromelain increased the flavor precursors and cocoa-bean flavors.
可可发酵是产生风味前体的关键过程。然而，由于产量低和发酵时间长，印度尼西亚的许多小农户直接将可可豆干燥而不进行发酵，导致风味前体和可可风味减少。因此，本研究旨在通过使用菠萝蛋白酶水解来提高未发酵可可豆的风味前体，特别是游离氨基酸和挥发性化合物。未发酵的可可豆先前分别用浓度为3.5、7和10.5 U/mL的菠萝蛋白酶水解4、6和8小时。然后分别以未发酵和发酵的可可豆作为阴性和阳性对照，对酶活性、水解度、游离氨基酸、还原糖、多酚和挥发性化合物进行分析。结果表明，在10.5 U/mL下水解6小时时水解度最高，为42.95%，尽管与在3.5 U/mL下水解8小时没有显著差异。这表明与未发酵的可可豆相比，还原糖含量更高，多酚含量更低。游离氨基酸也有所增加，尤其是疏水性氨基酸，如苯丙氨酸、缬氨酸、亮氨酸、丙氨酸和酪氨酸，以及理想的挥发性化合物，如吡嗪。因此，这表明用菠萝蛋白酶水解增加了风味前体和可可豆风味。
