Effects of selected salts on the cooking time, protein content and sensory properties of African yam beans and cowpeas

Abstract

Legumes (African yam beans and cowpeas) were boiled in tap water with different salts: NaHCO3, NaCl, CaCl2, Akanwa (trona1) at different concentrations2 of 0.2, 0.4 and 0.6 g/L, and the cooking time was monitored. Proximate analysis was conducted before and after treatment to determine the effects of these salts on the protein content. Sensory properties were also evaluated. Cooking times for the samples were significantly different (P < 0.05) when cooked in different concentrations of salts. The addition of Akanwa resulted in a shortening of the cooking time but the legumes were darkened. NaHCO3 and NaCl also reduced the cooking time while CaCl2 significantly increased the cooking time. The salts also affected the sensory properties. Results of protein analysis showed a significant difference between the treated samples at a concentration of 0.6 g/L. This suggests that heat and salt influence the protein content of legumes when cooked. NaHCO3‐treated samples required the least cooking time but samples treated with NaCl were more accepted. These results and their implications are important for those involved with emergency or disaster feeding.

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

“…Additional distilled water was added as necessary throughout cooking as follows: plain (control) 1.5 L, table salt 1.5 L, ground salt 1 L, and ash filtrate 1 L. Beans were tested for completion of cooking by hand and mouth feel by the first author and a local woman employed at Pope Paul Hospital, Atapara (Figure 1) who regularly cooks black beans. This method has been previously used for similar tests (Ankrah and Dovlo, 1978;Onwuka and Okala, 2003;Wanjekeche et al, 2003). Once drained and cooled, each pot of beans was divided into four separate airtight plastic containers for individual use at each site.…”

“…Salt is regularly used to decrease the cooking time of dried, hard-to-cook legumes (Uzogara et al, 1990;Onwuka and Okala, 2003;Mamiro et al, 2011). Depending on availability, people of different regions use several different types of salt or salt-like additives for cooking.…”

“…Ground salt is composed mainly of trona, a hydrated sesquicarbonate of sodium, which makes it highly alkaline (Makanjuola and Beetlestone, 1975). Alkalinity has been shown to have great influence on the softening of legumes, probably due to an effect on the starch gelatinization process (Wanjekeche et al, 2003) and in turn, decreases the necessary cooking time (Ankrah and Dovlo, 1978;Uzogara et al, 1990;Onwuka and Okala, 2003). As an alternative to ground salt, plant ash and/or plant ash filtrate is used as a traditional cooking additive in some areas of the world, including rural Africa (Kaputo, 1996;Wanjekeche et al, 2003;Mamiro et al, 2011).…”

“…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.…”

“…The colour of both treatments was unacceptable to panelists; a result commonly found with alkaline treatments. Onwuka and Okala (2003) looked at four parameters of palatability for different cooking treatments, including plain water, ground salt (akanwa), table salt, and two mixed salts (NaHCO 3 and CaCl 2 ). With respect to the first three treatments, respondents rated the legumes cooked with table salt as the most desirable across all parameters, while the legumes cooked with akanwa were deemed least acceptable.…”