Effect of steeping additives on tef starch extraction and its quality

Tef is an indigenous African cereal and considered as lost crop of Africa. There is no research on the effect of steeping additives on the quality of isolated tef starch. A white tef grain was milled and steeped in distilled water, sodium hydroxide, lactic acid, metabisulfite, and a combination of lactic acid and metabisulfite. A combination of metabisulfite and lactic acid improves the starch yield, but steeping with sodium hydroxide produces the highest starch purity (lowest protein content). Both the Rapid Visco Analyzer and a Rheometer showed similar pasting properties of starches independent of the treatment. The different steeping additives showed differences in pasting properties. Sodium hydroxide showed the highest peak, breakdown and set back viscosity compared to the other steeping additives. Extracted tef starches using sodium hydroxide as steeping additives also showed higher gelatinization temperatures. According to principle component analysis (PCA), the different properties of tef starch extracted with sodium hydroxide steeping is apparently due to its lower protein content. SEM and CLSM indicated that sodium hydroxide is a very effective solvent to solubilize the protein matrix surrounding the compound starch granule to produce more single starch granule during extraction. The low protein content probably result in faster water absorption and higher peak viscosity and lower pasting temperature. Different steeping additives can affect the functionality of tef starches and this need to be considered when comparing properties of starches extracted with different additives.National Research Foundation of South Africahttp://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1521-379Xhb201

V-amylose structural characteristics, methods of preparation,significance and potential applications

The amylose component of starch can form complexes known as V-amylose with amphiphilic or hydrophobic ligands. The V-amylose complexes are single, left-handed helices that are arranged as crystalline and amorphous lamellae, which may form distinct nano- or micron-scale structures. V-amylose has potential as a biomaterial for nanoencapsulation of sensitive bioactive and flavor ingredients, modification of rheological behavior of starch-containing products, reduction of starch retrogradation, and postprandial hyperglycaemia in diabetics. Various aspects of V-amylose structure, methods of preparation, factors that affect its formation, and the significance and potential applications of the V-amylose complexes are reviewed.University of Pretoria Commonwealth Scholarship Programme, DST/CSIR Nanotechnology Innovation Centre, and National Research Fund (NRF)http://www.tandfonline.com/doi/abs/hb201

The potential of strychnos spp L. utilization in food insecurity alleviation : A review

Abstract: Southern Africa has a vast resource of edible fruits, which can be useful in combating food and nutritional insecurity. However, many of these fruits are underutilized. An example of such underutilized fruit are the Strychnos fruits (monkey oranges). This review aims to highlight Strychnos spp as a potential food source to aid in the alleviation of food insecurity. This may promote more in-depth research on their nutritional value and processing procedures. Data bases such as Science Direct, Springer Link, Wiley online library and NCBI were used to construct this review. From the literature reviewed, there are numerous advantages within this genus, such as high fruit yields, drought tolerance and time of fruit maturity. Furthermore, little is known about the nutritional value of the fruit components (seeds, rind and pulp) and information regarding seed propagation is sparse, which has also hindered domestication of the genus. However, the genus appears to be a rich source of fibre, vitamin C and essential minerals such as iron. By expanding the knowledge surrounding the fruit of these species, their potential as a new food source may be exploited for its thickening properties, high micronutrient content and medicinal potential

Morphology, thermal properties and crystallization kinetics of ternary blends of the polylactide and starch biopolymers and nanoclay : the role of nanoclay hydrophobicity

Polylactide/butylated-starch/nanoclay (70/25.5/4.5 wt%) composites were prepared by melt blending with nanoclays of varying hydrophobicity. Electron microscopy studies indicated that the interphase boundary interaction was highest in the clay with intermediate hydrophobicity but decreased with clays of higher or lower hydrophobicity. Conventional and modulated differential scanning calorimetry studies showed that, in the case of composites, the change in the ratio of rigid and mobile amorphous fractions depends on the hydrophobicity of clays used for the preparation of blend composites. The mobile amorphous fraction related to the polylactide phase decreases in the case of intermediate hydrophobic clay compared with less and more hydrophobic clays or neat blend samples. Avrami bulk crystallization analysis and polarized optical microscopic observation demonstrated that hydrophobic clays hindered the crystallization of the PLA phase into the formation of disc-shaped spherulites. On the basis of obtained results, we propose a general understanding on how the morphology and thermal properties of the blend composites are related to the hydrophobicity of the nanoclays.Department of Science and Technology (HGERAOZ) , the Council for Scientific and Industrial Research and the University of Johannesburg (086310).http://www.elsevier.com/locate/polymer2016-08-31hb201

Discrimination of Musa banana genomic and sub-genomic groups based on multi-elemental fingerprints and chemometrics

The potential of unripe banana flour multi-elemental fingerprints for classifying banana genomic and subgenomic groups was assessed using chemometrics. The elemental concentration of N, P, K, Mg, Ca, Zn, Cu, Mn, Fe, and B in unripe banana flour from 33 banana varieties belonging to four genome groups and 11 subgenome groups were determined using Flame-atomic Absorption spectrometry and colorimetry. Principal component analysis (PCA) combined with linear discriminant analysis (LDA), support vector machine (SVM), and artificial neural network (ANN) was applied for classification with an 80:20 split between the calibration and verification sets (157 and 39 samples, respectively). The elements K, N, and Mg presented the highest mean concentrations of 1273 mg/100 g, 424 mg/100 g, and 132 mg/100 g, respectively. The classification model verification set samples were successfully classified based on their genome groups (100 % accuracy) and subgenome groups (78.95–100% accuracy) for PCA-LDA, PCA-ANN, and PCA-SVM models. The results demonstrate that multi-elemental fingerprinting combined with chemometrics can be employed as an effective and feasible method for classification of Musa genomic and sub-genomic groups

Nutraceutical properties of unripe banana flour resistant starch: a review

The present review provides a comprehensive discussion of the prebiotic, anti-diabetic, anti-colorectal cancer, and anti-cardiovascular disease effects of unripe banana flour resistant starch (BFRS). Unripe banana flour is considered a useful ingredient in the food industry because it has high levels of resistant starch (up to 68% w/w). The beneficial effects of BFRS against diabetes, obesity, cardiovascular disease, and colorectal cancer emanate from its resistance to hydrolysis and propensity to escape digestion in the upper-gastrointestinal tract, which delays glucose absorption and increases the concentration of colonic short-chain fatty acids (acetate, propionate, and butyrate). Therefore, BFRS can be recommended as an alternative functional ingredient in food products. However, more in vivo studies with BFRS should be conducted to ascertain the mechanisms that underly its beneficial effects and associated changes in the gut microbiome. The influence of other food product ingredients and food processing on BFRS efficacy and targeted production of specific short-chain fatty acids in the colon, needs to be investigated to optimize its application

Physicochemical and morphological properties of a small granule legume starch with atypical properties from wild mango (Cordyla africana L.) seeds : a comparison to maize, pea, and kidney bean starch

The physicochemical properties of wild mango (Cordyla africana L) seed starch are assessed and compared to bean, pea, and commercial maize starch. Scanning electron microscopy (SEM) and polarized optical microscopy (POM) show that wild mango starch granules are truncated (cap‐shaped) have smooth surfaces, and are much smaller (5.7 μm) than bean (28.2 μm), pea (23.0 μm), and maize (11.1 μm) starch granules. Wild mango starch had a higher (p ≤ 0.05) gelatinization temperature (differential scanning calorimetry‐DSC, Tp = 77 °C), but a lower enthalpy (ΔH = 10.7 J g−1) than pea, bean, and maize starches. X‐ray diffraction (XRD) reveals a C‐type crystalline pattern, while Fourier transform infrared spectroscopy (FTIR) indicates that the starch has a higher degree of short‐range order compared to bean, pea, and maize starches. Rapid visco analysis (RVA) shows that its peak paste viscosity (2811 cP) is significantly (p ≤ 0.05) higher than that of bean, pea, and maize starch. Wild mango starch is similar (p > 0.05) to maize starch in terms of RVA granule‐breakdown and gelation‐related parameters, and gel texture (firmness = 114.7 N and strength = 339.4 ± 16.5 J), differed significantly (p ≤ 0.05) from bean and pea starch.The National Research Foundation‐Grant Number 110674.http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1521-379Xhttp://www.starch-journal.com2019-11-01hj2018Physic

An Interesting Class of Porous Polymer-Revisiting the Structure of Mesoporous α-d-Polysaccharide Gels

The processes involved in the transformation of non-porous, native polysaccharides to their highly porous equivalents introduce significant molecular complexity and are not yet fully understood. In this paper, we propose that distinct changes in polysaccharide local short-range ordering promotes and directs the formation of meso- and micro-pores, which are investigated here using N2 sorption, FTIR, and solid-state 13CNMR. It is found that an increase in the overall double helical amylose content, and their local association structures, are responsible for formation of the porous polysaccharide gel phase. An exciting consequence of this local ordering change is elegantly revealed using a 19FNMR experiment, which identifies the stereochemistry-dependent diffusion of a fluorinated chiral probe molecule (1-phenyl-2,2,2-trifluoroethanol) from the meso- to the micro-pore region. This finding opens opportunities in the area of polysaccharide-based chiral stationary phases and asymmetric catalyst preparation

A proprietary alpha-amylase inhibitor from white bean (Phaseolus vulgaris): A review of clinical studies on weight loss and glycemic control

Obesity, and resultant health hazards which include diabetes, cardiovascular disease and metabolic syndrome, are worldwide medical problems. Control of diet and exercise are cornerstones of the management of excess weight. Foods with a low glycemic index may reduce the risk of diabetes and heart disease as well as their complications. As an alternative to a low glycemic index diet, there is a growing body of research into products that slow the absorption of carbohydrates through the inhibition of enzymes responsible for their digestion. These products include alpha-amylase and glucosidase inhibitors. The common white bean (Phaseolus vulgaris) produces an alpha-amylase inhibitor, which has been characterized and tested in numerous clinical studies. A specific and proprietary product named Phase 2® Carb Controller (Pharmachem Laboratories, Kearny, NJ) has demonstrated the ability to cause weight loss with doses of 500 to 3000 mg per day, in either a single dose or in divided doses. Clinical studies also show that Phase 2 has the ability to reduce the post-prandial spike in blood glucose levels. Experiments conducted incorporating Phase 2 into food and beverage products have found that it can be integrated into various products without losing activity or altering the appearance, texture or taste of the food. There have been no serious side effects reported following consumption of Phase 2. Gastro-intestinal side effects are rare and diminish upon extended use of the product. In summary, Phase 2 has the potential to induce weight loss and reduce spikes in blood sugar caused by carbohydrates through its alpha-amylase inhibiting activity