As the cell wall changes brought about by gamma-irradiation were associated with pectin solubilisation, this supports the phytate-phytase-pectin theory as a major cause of the HTC defect. However, the non-reversal of the defect in HTC susceptible cowpeas and the absence of an effect on CSP indicate that other mechanisms are involved in HTC defect development in cowpeas, possibly the formation of alkali-soluble, ester bonded pectins. © 2017 Society of Chemical Industry.

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Quinoa (Chenopodium quinoa Willd) is a nutritious pseudocereal that is more stress-tolerant compared with traditional cereals. It is an excellent example of a climate-smart crop that is more resilient to climate change compared with barley. The purpose of the study was to investigate the optimum malting conditions required to produce quinoa malt using barley as a control. Response surface methodology (RSM) was used to investigate the influence of the two malting parameters steeping time and germination time on Brix (wort extract), diastatic power (DP), and free amino nitrogen (FAN) of the malt. The temperature was set at 15°C during the steeping process. Steeping time ranging from 12 to 48 hours and germination time ranging from 24 to 96 hours were designed using a central composite design (CCD). The kilning temperature for all malts was 65°C. For quinoa malt, there was a notable weak positive correlation between germination time and Brix (r = +0.119). However, there was a strong positive correlation between steeping time and diastatic power (r = +0.893). A similar trend was noted for barley with a weak positive correlation between germination time and Brix (r = +0.142). A strong positive correlation was also recorded between steeping time and diastatic power (r = +0.897) during the malting of barley. There was a relatively stronger correlation between steeping time and FAN (r = +0.895) than germination time and FAN (r = +0.275) in quinoa malt. The optimum values for the malting of barley were 47.68 hrs steeping time and 82.55 hrs germination time with a desirability value of 1.00. The responses for the optimised barley malt were 8.25°Bx, 162.28 mg/L, and 271.69°L for Brix, FAN, and diastatic power, respectively. To produce quinoa malt with Brix, FAN, and diastatic power of 8.37°Bx, 165.60 mg/L, and 275.86°L, respectively, malting conditions of 47.69 hrs steeping time and 95.81 hrs germination time are required. It was noted that quinoa is a very good candidate for producing high-quality malt for the brewing process.

The global renewed interest in plant-based milk and products is increasing amongst health-conscious consumers. There is increased utilisation of generic probiotics in the processing of legume milk as alternatives to dairy milk are scarce in Africa. This study evaluated the probiotic potential, physicochemical, and sensory properties of novel fermented cowpea-peanut milk with Lacticaseibacillus rhamnosus Yoba. A 3 × 1 factorial design as ratio of cowpea-peanut milk (1 : 1, 2 : 1, 3 : 1v/v) and the application of 2% w/v L. rhamnosus Yoba obtained from Yoba for Life Foundation, Netherlands, was used. The chemical and mineral contents of the fermented cowpea-peanut milk was analysed using Association of Official Analytical Chemists (AOAC) methods. Quality parameters such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging rate, total antioxidant activity, antinutrient, and amino acids content were determined. The fermented cowpea-peanut milk samples had 7.7–8.1 log CFU/mL viable L. rhamnosus Yoba cells after fermentation. Nutrient content range was given in g/100 g: carbohydrate 5.18–6.05, crude fat 3.3–3.5, crude protein 5.6–7.1, ash 1.04–1.26, crude fibre 0.72–1.18, and total reducing sugars 1.80–2.20. Lysine, leucine, and methionine content was 6.30–7.31, 6.60–8.75, and 1.7–1.86 g/100 g, respectively. Phytic acid and trypsin inhibitor content range was 0.3–0.34 mg/100 g and 0.86–1.12 TIU/mg, respectively. Iron and potassium content (mg/100 g) was 0.48–0.58 and 202–243 with pH 4.1–4.2. DPPH free radical scavenging, and total antioxidant rate was 56–59% and 49–54%, respectively. Physicochemical parameters were significantly different ( p  < 0.05). The fermented cowpea-peanut milk had an acceptance rating of 78%. The successful application and consumer acceptability of the fermented cowpea-peanut milk has the potential to increase the utilisation of these legumes and enhance their market value.

Peanuts and peanut butter play an important role nutritionally in improving the diets of individuals in many parts of Africa, especially in the fight against child malnutrition. However, in developing countries such as Zimbabwe, most of the raw peanuts and peanut butter produced in backyard industries are sold in informal markets and rarely undergo formal safety inspection for aflatoxin contamination. The objective of the study was to determine the prevalence of aflatoxins in raw peanuts and backyard peanut butter sold at Mbare informal market. Ten (10) raw peanut samples and twenty (20) peanut butter samples were collected from Mbare informal market. Aflatoxin contamination was determined using liquid chromatography-mass spectrometry (LC-MS). The results revealed that sixty percent (60%) of the raw peanut samples were contaminated with total aflatoxin ranging from <0.75 to 426.4 μg/kg. One hundred percent (100%) of peanut butter samples were contaminated with total aflatoxins ranging from 4.7 μg/kg to 435.0 μg/kg. Aflatoxin B1 was the most prevalent aflatoxin in both raw peanuts (range, 1.2 μg/kg to 90.8 μg/kg) and peanut butter (range, 4.7 to 382.9 μg/kg). Forty percent (40%) of the raw peanuts and 95% of peanut butter samples exceeded the maximum limits of AFB1 as set by Zimbabwe legislation. The results suggest that raw peanuts and especially the peanut butter from backyard industries are heavily contaminated with aflatoxins and could constitute a possible health risk to consumers who regularly purchase these food commodities from informal markets.

To ensure production of quality malt that conforms to brewing requirements, the barley used should have minimal postharvest dormancy and be able to germinate rapidly and uniformly. The objective of the study was to compare the changes in seed germination, vigour trends, and storage stability of two-row Zimbabwean commercially grown malting barley varieties (Hope and Sierra), as the postharvest storage time increased. The two varieties were stored for 12 months, and at monthly intervals, germination index, capacity, and energy were determined. In addition, other quality parameters (protein content, screening, moisture content, water sensitivity, and insect damage index) were also assessed. Hope’s germination index improved with an increase in storage time from 8.67 at the beginning of the study to 9.18 at the end of the study, while that for Sierra diminished with storage from 9.35 to 6.71. Generally, water sensitivity improved with postharvest storage for both varieties. However, the germination energy for Hope diminished with increased postharvest storage compared to Sierra. Hope variety is the more suitable variety for extended postharvest storage than Sierra. However, Sierra variety is more suitable for early malting postharvest storage.