Modeling Growth Rate and Assessing Aflatoxins Production by Aspergillus flavus as a Function of Water Activity and Temperature on Polished and Brown Rice

Abstract: The aim of this study was to model the radial growth rate and to assess aflatoxin production by Aspergillus flavus as a function of water activity (a_w 0.82 to 0.92) and temperature (12 to 42 °C) on polished and brown rice. The growth of the fungi, expressed as colony diameter (mm) was measured daily, and the aflatoxins were analyzed using HPLC with a fluorescence detector. The growth rates were estimated using the primary model of Baranyi, which describes the change in colony radius as a function of time. Total of 2 secondary models were used to describe the combined effects of a_w and temperature on the growth rates. The models were validated using independent experimental data. Linear Arrhenius–Davey model proved to be the best predictor of A. flavus growth rates on polished and brown rice followed by polynomial model. The estimated optimal growth temperature was around 30 °C. A. flavus growth and aflatoxins were not detected at 0.82 a_w on polished rice while growth and aflatoxins were detected at this a_w between 25 and 35 °C on brown rice. The highest amounts of toxins were formed at the highest a_w values (0.90 to 0.92) at a temperature of 20 °C after 21 d of incubation on both types of rice. Nevertheless, the consistencies of toxin production within a wider range of a_w values occurred between 25 to 30 °C. Brown rice seems to support A. flavus growth and aflatoxin production more than the polished rice. Practical Application: The developed models can be used to estimate to what extent the change in grain ecosystem conditions affect the storage stability and safety of grains without the need for running long‐standing storage study. By monitoring the intergranular relative humidity and temperature at different locations in the storage facility and inputting these data into the models, it is directly possible to assess either the conditions are conductive for the growth of A. flavus or aflatoxin production.     

Distribution pattern of eight heavy metals in the outer and inner tissues of ten commonly used vegetables

This study reports the distribution of eight heavy metals (Cd, Co, Cr, Cu, Hg, Mn, Ni, and Pb) in the outer and inner tissues of ten different vegetables from the Qassim region of Saudi Arabia. The oven-dried (65°C, 48 h) vegetable samples were subjected to microwave acid digestion before heavy metals analysis using inductively coupled plasma optical emission spectrometry. The results showed that Co, Cd, and Pb were absent in the outer tissues of all the vegetables, whereas these elements were detected in the inner tissues of some vegetables in the ranges of 0.01–0.23 mg/kg wet weight, 0.03–0.42 mg/kg, and 0.02–3.44 mg/kg, respectively. The traces of Hg (1.83–3.59 μg/kg) were noticed in the outer tissues of all the samples; however, it was not detected in the inner tissues of vegetables. The variable distribution of heavy metals in different vegetables is influenced by several factors, including exposure route, physicochemical properties of heavy metals, species of crops, cultivation strategy, soil type, and growing conditions. In conclusion, although the representative samples of vegetables used in this study contained safe levels of Cd, Co, Ni, and Pb, higher than recommended upper limits of Cr, Cu, and Mn were observed in some vegetables. These findings suggested that regular monitoring of heavy metals in vegetables is important to safeguard consumers.     

Hypocholesterolaemic effect of yoghurt containing Bifidobacterium pseudocatenulatum G4 or Bifidobacterium longum BB536

The effect of a yoghurt supplement containing Bifidobacterium pseudocatenulatum G4 or Bifidobacterium longum BB536 on plasma lipids, lipid peroxidation and the faecal excretion of bile acids was examined in rats fed a cholesterol-enriched diet. After 8 weeks, the rats in the positive control (PC) group who were fed the cholesterol-enriched diet showed significant increases in plasma total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, and malondialdehyde (MDA). However, groups fed a cholesterol-enriched diet supplemented with yoghurt containing B. pseudocatenulatum G4 or B. longum BB536 had significantly lower plasma TC, LDL-C, very-low-density lipoprotein (VLDL) cholesterol, and MDA than had the PC group after 8 weeks of treatment. In addition, faecal excretion of bile acids was markedly increased in the rats fed the yoghurt containing B. pseudocatenulatum G4 or B. longum BB536 as compared to the PC and NC groups.     

Detection of fresh palm oil adulteration with recycled cooking oil using fatty acid composition and FTIR spectral analysis

There is a growing concern over the food safety issue related to increased incidence of cooking oil adulteration with recycled cooking oil (RCO). The objective of this study was to detect fresh palm olein (FPO) adulteration with RCO using fatty acid composition (FAC) and Fourier-transform infrared spectroscopy (FTIR) spectral analyses combined with chemometrics. RCO prepared in the laboratory was mixed with FPO in the proportion ranged from 1% to 50% (v/v) to obtain the adulterated oil samples (AO). FACs for FPO, RCO, and AO were determined using gas chromatography equipped with a flame ionization detector (GC-FID). The compositions of most fatty acids in RCO lied within the normal ranges of Codex standard, except for C8:0, C10:0, C11:0, C15:0, trans C18:1, and polyunsaturated fatty acids (PUFAs), C20:5. PUFAs showed a consistent decreasing trend with increasing magnitude of change with respect to increasing adulteration level and thus might be a good indicator for detecting FPO adulteration with RCO. The evaluation parameters (coefficient of determination, root mean standard error) of the FTIR-partial least square (PLS) model of palm oil adulteration with recycled oil are R² = 0.995 and 3.25, respectively. For FTIR spectral analysis, the distinct variations in spectral regions and aberrations in characteristic bands between FPO and RCO were observed. The optimized PLS calibration model developed from normal spectral of the combined region at 3602–3398, 3016–2642, and 1845–650 cm^?1 overpredict the adulteration level. On the other hand, the discriminant analysis classification model was able to classify the FPO and AO into two distinct groups. Improvement of the principles of combined techniques in authenticating AO from fresh oil is beneficial as a guideline to detect adulteration in cooking oil.     

Adhatoda vasica in Conjunction with Binary Combinations of Metal Salts and Biomordants as an Effective Textile Dye to Produce novel Shades on Wool

This study was undertaken to propose an alternative use of Adhatoda vasica leaves extract as a potential source of natural dye for the coloration of woolen yarn/fibers. Premordanting technique was adopted with double metal salt combinations of ferrous sulfate, stannous chloride, and potassium aluminum sulfate and double biomordant combinations of gallnut, pomegranate, and babool, to achieve dyed textile materials of acceptable colorimetric and fastness properties. Sixty-three sober and elegant shades were developed on wool by varying the nature and the concentration of mordants involved in the combinations. The hue of color developed was found to be in yellow-red coordinate of color space diagram. All the dyed samples presented excellent color strength (K/S) values and highest values were found in case of gallnut + pomegranate peel extract (PPE) combination. Biomordants produced altogether different behavior in comparison to metal mordants in the development of ecofriendly shades of different hue and tune. Majority of the dyed samples showed excellent fastness properties with respect to light, washing, and rubbing which confirmed the possibility of using A. vasica leaves extract as an effective yellow natural dye.     

Termites as human foods—A comprehensive review

Global food production is anticipated to rise along with the growth of the global population. As a result, creative solutions must be devised to ensure that everyone has access to nutritious, affordable, and safe food. Consequently, including insects in diets has the potential to improve global food and nutrition security. This paper aims to share recent findings by covering edible termites as the main aspect, from their consumption record until consumer acceptance. A total of 53 termite species are reported as edible ones and distributed in 6 biogeographic realms. Generally, termites have a nutrient composition that is suitable for human consumption, and cooked termites are a better dietary choice than their raw counterparts. Besides, increasing customer interest in eating termite-based food can be achieved by making it more palatable and tastier through various cooking processes, that is, boiling, frying, grilling, roasting, smoking, and sun-drying. Moreover, edible termites can also be used as a new source of medication by exhibiting antimicrobial activity. Regarding their advantages, it is strongly encouraged to implement a seminatural rearing system to sustain the supply of edible termites. Overall, this paper makes it evident that termites are an important natural resource for food or medicine. Hence, the long-term objective is to stimulate scientific inquiry into the potential of edible insects as an answer to the problem of global food security.     

Bi and Tri Metal Salt Combinations plus Colorants Extracted from Timber Industry Waste as Effective Dyeing Materials to Produce Novel Shades on Wool

This study was undertaken to propose alternative use for teak leaves, a timber industry byproduct, as potential dyeing source for wool fibers. The coloring potential of anthraquinone colorants from teak leaves were studied on wool with pre-mordanting method using double and triple mix metal salt combinations (ferrous sulphate, stannous chloride and potassium aluminum sulphate) as mordants. Thirty-six sober and elegant shades were developed on wool by varying the type of metal involved in combination as well as concentration of the dye. The hue of color developed ranged from light orange—brown to dark brown. The color strength (K/S) has been found to be very good in dyed woolen yarn samples and particularly was highest for iron + alum combination. Color fastness with respect to light exposure washing, rubbing for the developed shades ranged between good to very good, which confirmed the possibility of using waste leaves of Tectona grandis as a source of effective brown natural dye.     

Developing a Shade Range on Wool by Madder (Rubia cordifolia) Root Extract with Gallnut (Quercus infectoria) as Biomordant

Environmental issues inspire the revival of natural dyes that exhibit better biodegradability and more compatibility over synthetic ones. This research is aimed to investigate the effect of color and fastness properties on wool yarn substrate with natural anthraquinone colorants extracted from madder roots using gallnut (Quercus infectoria) extract as anchoring agent. Prior to the dyeing with Indian Madder (Rubia cordifolia), wool fibers were pre and post-treated with different concentrations of gallnut extract (viz 1–5% o.w.f) to get a broad range of beautiful and color fast shades. The feasibility of gallnut extract as an anchoring agent and its effect on color strength and color fastness to light, rubbing, and washing was investigated. Results of color characteristics showed that the color coordinates of the dyed samples were situated in the red-yellow quadrant of the CIELabcolor space. Bio-mordanting with gallnut extract produced shades of practically acceptable color depth, color fastness to light, washing and rubbing. Pre-treatment with gallnut extract is dominated over post-treatment in terms of better colorimetric and fastness results.