Oluwafemi Ayodeji Adebo

Review on Microbial Degradation of Aflatoxins.

ABSTRACT Aflatoxin (AF) contamination presents one of the most insidious challenges to combat, in food safety. Its adulteration of agricultural commodities presents an important safety concern as evident in the incidences of its health implication and economic losses reported widely. Due to the overarching challenges presented by the contamination of AFs in foods and feeds, there is an urgent need to evolve cost-effective and competent strategies to combat this menace. In our review, we tried to appraise the cost-effective methods for decontamination of AFs. We identified the missing links in adopting microbial degradation as a palliative to decontamination of AFs and its commercialization in food and feed industries. Cogent areas of further research were also highlighted in the review paper.

Aflatoxin B1 degradation by liquid cultures and lysates of three bacterial strains

Aflatoxin contamination remains a daunting issue to address in food safety. In spite of the efforts geared towards prevention and elimination of this toxin, it still persists in agricultural commodities. This has necessitated the search for other measures such as microbial degradation to combat this hazard. In this study, we investigated the biodegradation of aflatoxin B1 (AFB1), using lysates of three bacterial strains (Pseudomonas anguilliseptica VGF1, Pseudomonas fluorescens and Staphylococcus sp. VGF2) isolated from a gold mine aquifer. The bacterial cells were intermittently lysed in the presence and absence of protease inhibitors to obtain protease free lysates, subsequently incubated with AFB1 for 3, 6, 12, 24, and 48h to investigate whether any possible AFB1 degradation occurred using high performance liquid chromatography (HPLC) for detection. Results obtained revealed that after 6h of incubation, protease inhibited lysates of Staphylococcus sp. VGF2 demonstrated the highest degradation capacity of 100%, whereas P. anguilliseptica VGF1 and P. fluorescens lysates degraded AFB1 by 66.5 and 63%, respectively. After further incubation to 12h, no residual AFB1 was detected for all the lysates. Lower degrading ability was however observed for liquid cultures and uninhibited lysates. Data on cytotoxicity studies against human lymphocytes showed that the degraded products were less toxic than the parent AFB1. From this study, it can thus be deduced that the mechanism of degradation by these bacterial lysates is enzymatic. This study shows the efficacy of crude bacterial lysates for detoxifying AFB1 indicating potential for application in the food and feed industry.

Subcritical Water Extraction of Biological Materials

Extraction is a vital prerequisite in most scientific studies involving the isolation and analysis of compounds from biological/environmental systems. The use of large quantities of organic solvents in performing both conventional and modern methods of extraction of these substances stirs issues of safety, environmental concern and cost-effectiveness. Subcritical water extraction (SWE) offers a suitable, safe, cost-effective and environmentally safe alternative compared to other methods as it takes advantage of the special properties of supercritical water under high temperature and pressure conditions (100–374 °C, >50 bar) to extract non-polar analytes. This review presents a critical appraisal of the principles and dynamics of SWE, and the current applications as a viable tool in the extraction of compounds from various biological matrices. Although more research is needed to improve full SWE applications, its adoption in the extraction of phytochemicals as well as other bioactive molecules including mycotoxins from both plant and animal components seems promising and needs to be properly exploited.

Fermented and malted millet products in Africa: Expedition from traditional/ethnic foods to industrial value-added products

ABSTRACT With the prevalent food insecurity in Africa, there is a growing need to utilize the available crops to develop nutritious, affordable and palatable food for the populace. Millet is critical in this role, relative to its abundance in the continent and good nutritional composition. For ages, fermentation and malting have been traditionally used to transform millet into variety of produce. A paradigm shift has however occurred over the years, giving birth to new commercially available products. This review thus appraises and gives an overview of traditional and modern fermented and malted products. Although, millet has been diversified to several products, its major food uses are still restrained to traditional consumers and largely remains underutilized. Considering the potential embedded in this grain, it is important to explore this crop through the application of appropriate modern fermentation and malting technologies. This will ensure the availability of ready to eat (RTE) and ready to use (RTU) food products and to a large extent address the incessant food security challenges plaguing Africa.

Comparison of nutritional quality and sensory acceptability of biscuits obtained from native, fermented, and malted pearl millet (Pennisetum glaucum) flour

The effects of fermentation and malting on the proximate composition, mineral content, amino acids and total phenolic content of pearl millet flour and biscuits were studied. Consumer tests of the biscuits samples were also done using two sets of panelists. The results showed that fermentation and malting improved the crude fiber, crude protein, carbohydrate and energy values of the pearl millet flour. For the biscuit samples, the fermented and malted biscuits had higher moisture, crude protein, crude fiber and energy value with lower fat and ash content as compared to the biscuits obtained from native flour. Fermentation and malting were further observed to increase majority of the essential and non-essential amino acids. Consumer tests among the different set of panelists showed differences in the loading patterns as observed through principal component analysis. In conclusion, this study shows that fermentation and malting improves nutritional, health composition of pearl millet flour as well as the sensorial acceptability of subsequent biscuits.

Advances in Fermentation Technology for Novel Food Products

The relevance of fermentation as an important and key aspect of food processing cannot be overemphasized, as it enhances beneficial composition and ensures safety. Fermentation technologies have constantly evolved with advances effectively dealing with the challenges associated with the traditional food fermentation process. Over the years, concerted efforts, intensive scientific research and the advent of modern sophisticated equipment have addressed these challenges and progressed to new approaches for fermentation of foods, subsequently leading to the delivery of novel food products. These advancements are further fueled by competitiveness among industry players based on innovativeness, cost-cutting measures, profit and the understandable desire for process improvement, better yields and quality products. This chapter covers significant advancement and technological applications that can improve food fermentation processes that are applicable for the delivery of better, safer and cost-effective food products.

Influence of steeping duration, drying temperature, and duration on the chemical composition of sorghum starch

Abstract The quest for high‐quality starch that would meet the needs of manufacturers is ever increasing. This study investigated the effect of steeping duration, drying temperature, and duration on the chemical properties of sorghum starch, to possibly alter the characteristics of sorghum starch for food applications. Steeping duration, drying temperature, and drying time of starch isolation were optimized using a central composite design and nine parameters including pH, amylose content, moisture, protein, ash, crude fiber, fat, carbohydrate, and total energy determined. Results obtained showed that most of the parameters were majorly influenced by steeping and drying duration. Steeping duration significantly (p < .05) increased the moisture, protein, and ash content of the sorghum with a corresponding decrease in pH values. The obtained experimental and predicted values of the investigated parameters were similar, with statistical indices indicating the relative validity of the generated models [absolute average deviation (AAD between 0 and 0.20), bias factor (B f, 1–1.02), and accuracy factor (A f, 1–1.21)]. The varying values of the parameters obtained indicates the potential use of the sorghum starches as thickeners, starch substitutes, and for other desired roles in food processing.

Equilibrium sorption isotherms of Moringa oleifera leaves at different temperatures

Adsorption and desorption isotherms for Moringa oleifera leaves were investigated using concentrated H2SO4 solutions to vary the micro-climate over different temperatures (27, 32, 37°C) and water activity (aw) (0.1–0.8). Plots of equilibrium moisture content (EMC) against aw were used to generate isotherm curves, local isotherm (Li) concept and stability. The experimental data obtained were compared with four widely recommended models in the literature for food sorption isotherms [GAB, modified GAB (MGAB), modified Oswin (MOE) and OSWIN models]. Results obtained showed that the moisture sorption isotherms were sigmoidal in shape and were influenced by temperature. The four sorption models adequately predicted the adsorption and desorption isotherms for Moringa oleifera leaves at the evaluated temperatures, with R2 values between 0.980 and 0.998. The sequence in which the evaluated models effectively fitted the moisture sorption, were GAB, MGAB, MOE and OSWIN models, with GAB being the best. While the GAB model was most suitable for fitting the adsorption [Mean square error (MSE = 183.08), standard error of estimate (SEE = 549.24), R2 = 0.980)], MGAB was better for desorption isotherm [(MSE = 141.950), SSE = 425.86), R2 = 0.998] of Moringa oleifera leaves under practical storage temperature and water activity used in this study.

Profiling of volatile flavor compounds in nkui (a Cameroonian food) by solid phase extraction and 2D gas chromatography time of flight mass spectrometry (SPME-GC×GC-TOF-MS)

Abstract The objective of this study was to investigate the volatile flavor compounds of nkui, a Cameroonian food, using solid phase microextraction (SPME) and a two‐dimensional gas chromatography time of flight mass spectrometry GC×GC‐TOF‐MS system. Using SPME, volatile compounds were extracted from nkui and analyzed by GC×GC‐TOF‐MS. The data retrieved revealed the presence of flavor volatiles including acids (20%), alcohols (4%), aldehydes (10%), aromatic compounds (4%), esters (7%), furans (4%), ketones (11%), terpenes and terpernoids (27%). Although the terpene compounds were the most predominant, an ester (linalyl acetate) had the highest percentage of 19%, conferring a sweet, green and citrus flavor. Results obtained from this study suggest that the characteristic flavor of nkui was due to the combination of different volatile flavor compounds, which contributed to its aroma. Considering the medicinal importance of these compounds, their presence positions nkui as a vital food source with health benefits and medicinal properties.

Process optimization of extrusion variables and its effect on properties of extruded cocoyam (Xanthosoma sagittifolium) noodles

Abstract The current industrial demand for starchy foods has been dominated by other roots and tubers, while cocoyam, despite being rich in fiber, minerals, and vitamins has remained under exploited. In this study, the effect of feed moisture content (FMC), screw speed (SS) and barrel temperature (BT) on the quality characteristics of cocoyam noodles (proximate, thermo‐physical, physicochemical, texture, color, extrudate properties, and sensory characteristics) were investigated using central composite design (CCD) of response surface methodology (RSM). Flour was produced from fresh tubers of cocoyam (Xanthosoma sagittifolium) and subsequently processed into noodles using a twin screw extruder. Results showed that the proximate compositions, thermo‐physical, physicochemical properties, and color of the cocoyam noodles were significantly (p < 0.05) influenced by the extrusion process variables. The texture and extrudate properties of cocoyam noodles were equally significantly (p < 0.05) different. The experimental data obtained and predicted values of the response models were comparable, with statistical indices [absolute average deviation (AAD, 0–0.23), bias factor (B f, 1–1.08), and accuracy factor (A f, 1–1.23)] indicating the validity of the derived models. The optimal extrusion processing conditions for quality cocoyam noodles were FMC, SS, and BT of 47.5%, 700 rpm and 50°C, respectively, as cocoyam noodles obtained at these conditions had comparable properties and were most preferred and accepted by the sensory panelists.