Influence of Processing Methods on the Tannin Content and Quality Characteristics of Cashew By-Products
Emelike N.J.T
Department of Food Science and Technology, Rivers State University of Science and Technology, Port Harcourt, Nigeria
Ebere C.O
Department of Food Science and Technology, Rivers State University of Science and Technology, Port Harcourt, Nigeria
Keywords: Processing methods, Tannin content, Chemical compositions, Sensory properties, Physiochemical characteristics, Cashew kernel, Cashew oil.
Abstract
Cashew (Anacardium occidentale L.) kernel was processed using sand and gari roasting methods to study the chemical compositions, tannin reduction and sensory properties of the kernel in comparism with the reference sample (imported cashew kernel). Oil was extracted from part of the gari roasted sample. Soybean flour was processed, the oil equally extracted and the physiochemical characteristics of the oils studied. From the result, there was no significant difference (p>0.05) in all the chemical compositions studied irrespective the processing method from the reference sample. Tannic acid of the kernel was observed to reduce to 0.1% in the gari roasted kernel and showed no significant difference to the imported kernel (0.1%). However, sand roasted cashew kernel had the highest tannic acid value of 0.2%. Sensory attributes of colour, flavour and general acceptability of the gari roasted kernel (4.50, 4.70 and 4.50, respectively) compared well with the imported kernel. All the sensory attributes of the sand roasted kernel was significantly lower compared to the reference sample. The physiochemical characteristics of the golden yellow colour cashew kernel oil showed that the oil is high in acid value (1.57mg KOH/g), saponification value (218.6mg KOH/g), specific gravity at 25oC of water (0.91%) and iodine value of 144.021gl2/100gm. This is an indication that gari roasting method is the best processing method in terms of the tannin reduction and the sensory characteristics.