A comparative study on the physico-chemical quality indices of whole, commercial and refined wheat flours: Emphasis on essential amino acid index for three major penaeid shrimp species cultured in India
The physico-chemical characteristics of three different types of refined wheat flours (RWF-1, RWF-2 and RWF-3) were assessed to ascertain its suitability in shrimp feed along with three different types of whole (WWF-1, WWF-2 and WWF-3) and commercial (CWF-1, CWF-2 and CWF-3) wheat flours, and the essential amino acid index (EAAI) was determined based on the dietary requirement of three major penaeid shrimp species cultured in India viz., Penaeus vannamei, Penaeus indicus and Penaeus monodon. Results revealed that the fineness of WWF and RWF was 100% and alcoholic acidity exceeded an ideal level of 0.1% in WWF-2, CWF-3 and RWF-1. RWF had a low (p<0.05) water absorption (51.88-53.93%) and high bulk density (782.92-794.92 g l-1) compared to others. The moisture content was high (p<0.05) in RWF, whereas carbohydrate, protein, lipid and ash were found to be high in WWF. Of all the analysed samples, RWF had a higher (p<0.05) content of wet (28.56-31.82%) and dry (8.90-10.44%) glutens. Among the essential amino acids (EAA), arginine, lysine and methionine did not vary between the samples tested, while others showed significant (p<0.05) difference. EAAI was affected by the species (p=<0.001) but not by the flours (p = 0.173) and their interactions (p = 0.468). Both P. vannamei and P. indicus had a significantly higher EAAI (0.899 and 0.900, respectively) compared to P. monodon (0.862). Regression analysis showed a positive higher correlation between protein and EAA (r = 0.851) but EAA and its index were negatively correlated (r = 0.3464). Calories from carbohydrates were high in RWF (79.04-81.19%), but the reverse was true for protein and lipid in both WWF and CWF. Results conclude that RWF could be used for shrimp feed production, but ascertaining the processing effect on its utility by shrimps is essential.
Keywords: Chemical composition, Essential amino acid index, Penaeid shrimps, Physical properties, Wheat flour