Effect of Different Storage and Cooking Methods on Some Biochemical, Nutritional and Sensory Characteristics of Cowpea (Vigna unguiculataL. Walp)

Abstract

Cowpeas stored in a hermetic container, jute bag and nitrogen atmosphere at ambient (temperature 21-31"C, relative humidity 72-86%) for 6 months were evaluated for changes in proximate composition, nutritional and sensory qualities when cooked by different methods. Nitrogen storage effectively preserved the chemical composition of the cowpeas and maintained grain with better cooking characteristics than cowpeas stored in other systems. Cooking methods and the storage conditions influenced the cooking time and significantly affected the thiamine loss, rate of proteolysis, in-vitro protein digestibility and sensory qualities of the cowpeas. Cooking the stored unsoaked cowpeas with local rock salt to reduce cooking time had a deleterious effect on both the nutritional and sensory qualities of cowpeas.

Crop ash filtrate influence on cooking time and sensory preferences for dried black beans (Phaseolus vulgaris L.)

“…Women are responsible for all cooking related activities for the household including collection of firewood and water. These concentrations of table salt (0.25% w/v), ground salt (0.25% w/v), and ash filtrate (2.25% v/v) were also comparable with similar studies (Onayemi et al, 1986;Wanjekeche et al, 2003).…”

“…Texture was measured on two accounts; both for hardness, from too hard (1) to good (5) and for softness, from too soft (1) to good (5), in order to identify beans which were both deemed to be either under or over-cooked. The scale and categories were adapted from previous successful methodologies (Silva et al, 1981;Onayemi et al, 1986;Onwuka and Okala, 2003).…”

“…The colour of beans cooked with akanwa was too dark and the flavour less palatable than either the control or beans cooked with table salt and only the texture of the akanwa beans was comparable to the other samples. Onayemi et al (1986) also found poor acceptability for cowpeas cooked in either local rock salt (ground salt) or alkali potash (sodium carbonate; functionally similar to plant ash). Prior research using sensory evaluation tests have shown that traditional salts are not preferred, despite a strong cultural presence and continued use.…”

“…Prior research using sensory evaluation tests have shown that traditional salts are not preferred, despite a strong cultural presence and continued use. Further, over addition of these salts contributes to a sharp, unpleasant taste (Onayemi et al, 1986), possibly due to the high alkalinity. For this reason, bitterness was added as a parameter in this study.…”

“…Sensory evaluation for cooked legumes has previously included colour, taste, texture, and overall acceptability (Silva et al, 1981;Onayemi et al, 1986;Onwuka and Okala, 2003). However, relatively few studies have focused on the use of traditional salts in cooking legumes, and even fewer have included sensory evaluation as a component of the study.…”