Adebayo Abass

Quantitation of multiple mycotoxins and cyanogenic glucosides in cassava samples from Tanzania and Rwanda by an LC-MS/MS-based multi-toxin method

A multi-mycotoxin method based on liquid chromatography/tandem mass spectrometry (LC-MS/MS) was used for a mycotoxin survey in 627 samples of processed cassava collected from different districts across Tanzania and Rwanda after the method performance for this matrix had been determined. Matrix effects as well as extraction efficiencies were found to be similar to most other previously investigated matrices with the exception of distinct matrix effects in the negative ionisation mode for early eluting compounds. Limits of detection were far below the regulatory limits set in the European Union for other types of commodities. Relative standard deviations were generally lower than 10% as determined by replicates spiked on two concentration levels. The sample-to-sample variation of the apparent recoveries was determined for 15 individually spiked samples during three different analytical sequences. The related standard deviation was found to be lower than 15% for most of the investigated compounds, thus confirming the applicability of the method for quantitative analysis. The occurrence of regulated mycotoxins was lower than 10% (with the exception of zearalenone) and the related limits were exceeded only in few samples, which suggests that cassava is a comparatively safe commodity as regards mycotoxins. The most prevalent fungal metabolites were emodin, kojic acid, beauvericin, tryptophol, 3-nitropropionic acid, equisetin, alternariol methylether, monocerin, brevianamide F, tenuazonic acid, zearalenone, chrysophanol, monilifomin, enniatins, apicidin and macrosporin. The related concentrations exceeded 1 mg kg–1 only in few cases. However, extremely high levels of cyanogenic plant toxins, which had been previously added to the method, were observed in few samples, pointing out the need for improved post-harvest management to decrease the levels of these compounds. Graphical Abstract

Assessment of the potential industrial applications of commercial dried cassava products in Nigeria

Variations in the functional and pasting properties of four groups of commercial dried cassava product in Nigeria were evaluated in this study, to explore their potential for use as industrial raw materials. In total, 692 products were analyzed using standard analytical methods. The functional and pasting properties of the samples were found to vary significantly (p < 0.05). Toasted cassava was found to have the highest water absorption capacity, at 467.42 %, and dried cassava the lowest, at 252.57 %. Conversely, dried cassava was found to have the highest peak and breakdown viscosities, and toasted cassava the lowest. A significant (p < 0.01) positive correlation was found to exist between dispersibility and the swelling power (r = −0.93) and solubility index (r = −0.84) of the cassava products. Meanwhile, the correlation between dispersibility and the peak (r = −0.75) and breakdown (r = −0.72) viscosities was positive and significant (p < 0.05). Therefore, the authors of this study conclude that user industries such as the food, paper, adhesives, textiles and plywood sectors might require information on the pre-processing of cassava-based feedstock, so as to predetermine the technical usability of such raw materials within their industrial processes.

Screening of some cassava starches for their potential applications in custard and salad cream productions

Custard powder and salad cream are two food products commercially manufactured using different quantities of corn starch. This study aimed at determining the physicochemical properties of some starches extracted from some white and yellow root cassava varieties. The prospective applicability of the cassava starches in custard powder and salad cream production was also determined. The physical, chemical and functional properties of eight cassava starches were determined using standard analytical procedures. Sensory acceptability of the products was also determined using untrained consumer group. Products made from corn starch were used as the reference samples. The physical, chemical and functional properties of the cassava starches varied significantly (p < 0.05). The results of multivariate data analysis (principal component and cluster analyses) showed that it was difficult to completely discriminate starches from the yellow fleshed and white fleshed cassava roots. Texture was the most important sensory attribute determining the two products’ acceptability. Starch powder dispersibility was found to have significant influence (p < 0.05) on the sensory acceptability of the two products. However, starch from a yellow fleshed root (TMS 01/1368) was the most preferred for salad cream making while starch from a white fleshed root (TMS 30572) was the most preferred for making custard powder. The starches showed high potential to replace corn starch for the respective product manufacture.

Occurrence of Regulated Mycotoxins and Other Microbial Metabolites in Dried Cassava Products from Nigeria

Dried cassava products are perceived as one of the potential sources of mycotoxin ingestion in human foods. Processing either contributes to the reduction of toxins or further exposes products to contamination by microorganisms that release metabolic toxins into the products. Thus, the prevalence of microbial metabolites in 373 processed cassava products was investigated in Nigeria. With the use of liquid chromatography tandem-mass spectrometry (LC-MS/MS) for the constituent analysis, a few major mycotoxins (aflatoxin B1 and G1, fumonisin B1 and B2, and zearalenone) regulated in food crops by the Commission of the European Union were found at concentrations which are toxicologically acceptable in many other crops. Some bioactive compounds were detected at low concentrations in the cassava products. Therefore, the exposure of cassava consumers in Nigeria to regulated mycotoxins was estimated to be minimal. The results provide useful information regarding the probable safety of cassava products in Nigeria.

Assessment of heavy metals and microbial contamination of gari from Liberia

Abstract Cassava is a staple mostly eaten in the form of gari, after rice in Liberia. The local method of gari processing often leads to product contamination, thus, a study was done to assess the heavy metals and microbial contamination of gari in eight counties of the country. A total of sixty‐one gari samples were collected and packaged in an airtight polyethylene bag for analyses, using standard methods. Results depict that the mean of the heavy metals in the gari samples is iron (Fe) 43.87 ppm, copper (Cu) 0.94 ppm, zinc (Zn) 5.49 ppm and aluminum (Al) 257.45 ppm. Yellow gari had the highest Fe (64.90 ppm), Cu (1.25 ppm) and Zn (7.85 ppm) content, but with the least Al content (87.15 ppm). The Fe content was lower in groundnut‐fortified gari (42.93 ppm), and the Cu (0.70 ppm) and Zn (3.50 ppm) content were lower in groundnut‐moringa‐fortified gari. The samples and counties have no significant statistical effect (p > .05) on the heavy metals composition of the products. No microbial growth was observed in groundnut‐fortified and groundnut‐moringa‐fortified gari but with coconut‐fortified gari having the highest total fungi count of 800 CFU/g. The major fungi identified in the gari samples are Penicillium and Aspergillus spps., but with their counts within the regulated level. Therefore, the gari consumed in Liberia are safe except for the high Fe and Al content, which needs to be addressed with the use of unpainted stainless steel materials as food contact surfaces.

Effect of soy protein isolate on the functional, pasting, and sensory acceptability of cassava starch‐based custard

Abstract Fortification of custard powder (CP) with protein from cheap sources such as soybean could potentially improve its nutritive value but may alter its functional and sensory properties. This study was therefore conducted to determine the effect of soy protein isolate (SPI) inclusion (0%–20%) on some functional and sensory properties of cassava starch‐based CP. Functional, pasting, and sensory acceptability were determined using standard methods. Increase in soy protein isolate significantly (p < .05) decreased dispersibility, packed bulk density, swelling power, peak, trough, breakdown, final, and setback viscosities, but increased least gelation concentration, water absorption capacity, and solubility index. This study further showed that despite increasing addition of SPI up to 20%, sensory acceptability of the cassava starch‐based CP formulations did not differ significantly, and most of them had very similar acceptability when compared to that of corn starch‐based CP.

Adding value through the mechanization of post-harvest cassava processing, and its impact on household poverty in north-eastern Zambia

ABSTRACT This article investigates the impact of adopting a mechanized cassava processing system on household poverty levels in Zambia. An Foster, Greer and Thorbecke (FGT) poverty measure was used to compare poverty levels among households using a mechanized cassava processing system against those households using a nonmechanized process. Based on the FGT poverty measure’s specifications, a significantly lower poverty status of 49% was found among households using the mechanized process when compared to the 58% found among households using the nonmechanized process. The significant factors contributing to these differences in poverty levels include whether households are using a mechanized process or not, the number of years’ schooling among household members, the number of years’ farming experience, household income and membership of associations. The study concludes that the mechanization of cassava processing, particularly if done on the right scale, can transform primary production activities, in turn leading to higher incomes and reduced poverty levels in rural villages. Thus, policies should be introduced aimed at encouraging the promotion of mechanized post-harvest cassava processing technologies among rural households, so as to enhance crop productivity and household income levels, as well as reduce poverty among rural households.

The impact of mechanized processing of cassava on farmers’ production efficiency in Uganda

ABSTRACT The study investigates the impact of adopting mechanized processing of cassava on farmers’ production efficiency in Uganda. A stochastic production function, using translog functional form, was used to compare efficiency measures of farmers in mechanized cassava-processing villages compared with the farmers in nonmechanized cassava-processing villages in 2014. Given the specification of the translog production function, the mean technical efficiencies of the farmers were 0.69 and 0.52 in mechanized and nonmechanized villages, respectively. The significant determinants of technical inefficiency among the respondents are farming experience, education, membership of farmer association, access to markets, sale of cassava to processors and farmers who planted cassava as sole crop are all negative, which confirm to a priori expectations and significant at different levels. The policy implication of the study is that mechanization of cassava processing, particularly if done at the right scale, could create demand that can transform primary production for increased yields, higher incomes and production efficiency of smallholder farmers who constitute a significant proportion of Uganda’s agricultural sector.