and TAA of powder products at three levels of maltodextrin concentration and at five inlet air tem- peratures. From Fig. 6, similar TAA values correspond with differ- ent TCC’s at different maltodextrin concentrations were observed. This demonstrates the effect of protection by the encapsulating agent. Furthermore, TAA in the powders not only based on the TCC but also other antioxidative components in Gac powders such as a-tocopherol (vitamin E) and fatty acids which also benefitted from the encapsulation and exert synergistic effects.
It is clear that there was strong correlation between TCC and TAA (R2 = 0.915–0.948). The highest correlation was found at the lowest maltodextrin concentration. Moreover, according to a Pear- son correlation test between TCC and TAA results for different dry- ing conditions, the Pearson correlation coefficient was 0.482 and significant at the level 0.01 level (2-tailed). The positive correlation means that with increasing TCC, the TAA in the spay-dried Gac fruit powders also increases. Likewise, Chanwitheesuk et al. (2005) re- ported that a high correlation between total carotenes and the antioxidant index was found in Piperaceae (R = 0.99) and in Cucur- bitaceae (R=0.87), however, the low correlation was found in Umbelliferae (R = 0.46). In contrast to this result, a negative correla- tion between total carotenoids and antioxidant activity in guava fruit extract was observed by Thaipong et al. (2006). The different result is likely to be due to the different raw materials and the ef- fects of encapsulation.
Moreover, total colour difference of reconstituted powder in corresponding to the feed juice strong negatively correlated to TAA (r =