Safety of African grown rice: Comparative review of As, Cd, and Pb contamination in African rice and paddy fields.

This review aimed to investigate the reported concentrations of arsenic (As), cadmium (Cd), and lead (Pb) in rice cultivated in Africa and African rice paddies compared to other regions. It also aimed to explore the factors influencing these concentrations and evaluate the associated health risks of elevated As, Cd, and Pb exposure. Relevant data were obtained from electronic databases such as PubMed, Scopus, and Google Scholar using specific keywords related to arsenic, cadmium, lead, rice, Africa, paddy, and grain. While the number of studies reporting the concentrations of As, Cd, and Pb in rice and rice paddies in Africa is relatively low compared to other regions, this review revealed that most of the African rice and paddy soils have low concentrations of these metals. However, some studies have reported elevated concentrations of As, Cd, and Pb in paddy fields, which is concerning due to the increased use of agrochemicals containing heavy metals in rice production. Nonetheless, agronomical interventions such as implementing alternate wetting and drying water management, cultivating cultivars with low accumulation of As, Cd, and Pb, amending rice fields with sorbents, and screening irrigation water can limit the bioaccumulation of these carcinogens in paddy fields using phytoremediation techniques. Therefore, we strongly urge African governments and organizations operating in Africa to enhance the capacity of rice farmers and extension officers in adopting approaches and practices that reduce the accumulation of these carcinogenic metals in rice. This is essential to achieve the sustainable development goal of providing safe food for all.

Reduction of aflatoxins during brewing of a Malawian maize-based non-alcoholic beverage, thobwa.

This study reports onthe effect of various production steps on levels of aflatoxins during preparation of thobwa, a traditional maize-based fermented non-alcoholic beverage, brewed across Malawi. The effect of boiling, fermentation and their interaction on the level of aflatoxins, the trends of aflatoxin reduction during brewing, and the distribution of aflatoxins between the solid and liquid phases of the beverage were studied using VICAM AflaTest immunoaffinity fluorometric assay. Fermenting and boiling thobwa pre-mix-, with initial aflatoxin content of 45-183 µg/kg, resulted in aflatoxin reduction of 47% (13-61 µg/kg) on average. Fermentation and boiling contributed about 20 and 33% aflatoxin reduction, respectively, but without interactive effect between the two factors. Fermenting the thobwa for 24 h led to further reduction of aflatoxins to about 37% of the initial content, and remainedconstant for up to 8 days. Thobwa is a popular beverage in Malawi which is consumed in large quantities by all gender categories including infants, therefore the presence of aflatoxins may constitute a significant health risk factor. This study highlights the need to use raw materials with low levels of aflatoxins for production of maize-based non-alcoholic beverages to ensure consumer safety.

Acceptability of orange corn-common bean as an alternative to corn-soybean complementary porridge in Malawi.

This study assessed the acceptability of porridge from a corn-common bean flour blend to increase the diversity of complementary foods in Malawi. Porridges prepared using commercial corn-soybean flour (C-CSB), homemade orange corn-soybean flour (H-CSB), and orange corn-common bean flour (CCBB) were evaluated by 101 pairs of mothers and their respective children aged from 6 to 24 months. A home use test (HUT) setup was used in this study, and the flours were given sequentially to participating households following a randomized complete block design. Each sample type was evaluated for 3 days in a row followed by a 1-day break (washout period) between sample types. Based on aggregate mean scores, all the samples were liked by both the children and their mothers. However, clustering results revealed two distinct consumer segments for mothers as well as for children. Most of the mothers (59.4% in cluster 1) liked all the samples, while the minority (cluster 2) were neutral (neither like nor dislike) regarding the H-CSB porridge. Likewise, most children (66.3% in cluster 2) liked all the samples, while the rest in cluster 1 did not like CCBB porridge. Infants (≤12 months) and those from food-insecure households, respectively, were 5.42 and 6.75 times more likely to like the CCBB porridge than their counterparts. The study has demonstrated the potential of introducing CCBB complementary porridge in Malawi and possibly in other countries with similar food preferences and socioeconomic stature. PRACTICAL APPLICATION: The study provides a solution to the limited diversity of complementary foods in sub-Saharan Africa and Malawi in particular. The findings can help food scientists, nutritionists, marketers, and policymakers develop strategies for promoting the consumption of orange corn-common bean porridge. Furthermore, the findings can inform decisions on commercializing orange corn-common bean flour by flour processors.

Polyphenolic inhibition of enterocytic starch digestion enzymes and glucose transporters for managing type 2 diabetes may be reduced in food systems.

With the current global surge in diabetes cases, there is a growing interest in slowing and managing diabetes and its effects. While there are medications that can be used, they have adverse side effects such as hypoglycemia and weight gain. To overcome these problems, bioactive compounds commonly found in fruits, vegetables and cereal grains are used to slow starch digestion and transport of simple sugars across the intestinal epithelia thereby reducing plasma blood glucose spike. These effects are achieved through inhibition of amylases, glucosidases and glucose transporters present in the gastrointestinal tract and brush boarder membrane. The extent of inhibition by polyphenols is dependent on molecular structure, doses and food matrix. Glycemic lowering effect of polyphenols have been demonstrated both in in vivo and in vitro studies. However, when these compounds are incorporated in food systems, they can interact with other polymers in the food matrix leading to lesser inhibition of digestion and/or glucose transporters compared to isolated or pure compounds as often witnessed in most in vitro studies.