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

The role of indigenous knowledge (IK) in adaptation to drought by agropastoral smallholder farmers in Uganda

44-52Majority of agro pastoral smallholder farmers in developing countries are characterised by low pay status, high illiteracy levels and are tied to cultural beliefs and spirits. These drawbacks have led them into using more indigenous knowledge as a way of adapting to droughts. This study explored the contribution of IK in enhancing farmer’s resilience to drought in crop and livestock production systems in semi-arid areas. The objectives were: (i) to examine the agro pastoral farmer’s perceptions of drought indicators and associated impacts and (ii) determinants for the adoption of indigenous knowledge drought adaptation responses. Socio-economic data was collected using oral interviews. The farmers (240) were selected using random sampling procedures and subjected to structured questionnaires and key informant guides. This study highlights that the droughts experienced were perceived to be more severe, recurrent and pervasive but also erratic. The IK drought signs were: flowering of wild plants, blowing of strong winds and appearance of flying and crawling insects. In crop-based systems, droughts reduced yields, caused plant stunted growth, increased incidences of diseases and invasive weed species. In livestock, droughts reduced surface water levels, lowered milk and beef yields, and increased diseases. The farmers reacted to droughts by practicing indigenous agro forestry, mulching, changing planting time, crop rotation and hoeing of trenches to control fires and pests/diseases. They also took their animals to wetlands for foraging and drew water for animals to drink. The uptake of IK drought adaptation practices was related to: household size, personal farming life experience, gender and age of the agro pastoral farmers. Therefore, employing IK drought adaptation responses is an important step towards increasing the resilience of agro pastoral smallholder farmers but also the conservation of IK for forthcoming generations

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

Effect of the incorporation of surfactants on the physical properties of corn starch films

[EN] The effect of surfactant addition on structural, mechanical, optical and barrier properties of corn starch-glycerol based films was studied. Sorbitan monopalmitate, monostearate or monooleate were incorporated into starch-glycerol (1:0.25) at a surfactant:starch ratio of 0.15:1. The film forming dispersions (FFD) were characterized as to rheology, ζ-potential, particle size distribution and contact angle. Film characterization was carried out at 1 and 5 storage weeks (at 25ºC and 53 % relative humidity). Surfactants led to different particle size distribution, zeta potential and viscosity in FFD, and film extensibility, depending on their hydrophobicity and melting properties. Their incorporation to the corn starch-glycerol films produced a coarser film microstructure due to the appearance of free surfactant aggregates or V-amylose inclusion complexes which produce discontinuities in the amorphous continuous matrix. The size of these crystalline complexes was smaller for the surfactant with the lowest hydrophobicity with saturated fatty acid (span 40). This contributed to decrease the WVP values with respect to surfactant-free film. Films containing surfactants were less hard, resistant and extensible, and more permeable to oxygen, than surfactant-free films, but they did not notably affect the film gloss and transparency. Saturated fatty acid compounds with higher melting temperature are recommended to ensure a finer microstructure in the final film which favours water barrier efficiency.The authors acknowledge the financial support from Spanish Ministerio de Educacion y Ciencia throughout the project AGL2010-20694. Rodrigo Ortega-Toro thanks Conselleria de Educacio de la Comunitat Valenciana for the Santiago Grisolia grant.Ortega Toro, R.; Jiménez Marco, A.; Talens Oliag, P.; Chiralt, A. (2014). Effect of the incorporation of surfactants on the physical properties of corn starch films. Food Hydrocolloids. 38:66-75. doi:10.1016/j.foodhyd.2013.11.011S66753

Properties of biopolymer dispersions and films used as carriers of the biocontrol agent Candida sake CPA-1

[EN] The use of biocontrol agents (BCA) for controlling plant diseases is an alternative to reduce the use of pesticides. Their performance can be improved when applied in combination with coatings. Films and coatings formulated from different biopolymers were characterized as to their barrier and optical properties to analyse their impact on fruit when applied as carriers of the BCA Candida sake CPA-1. The properties of the film-forming dispersions were more affected by the type of polymer than by the incorporation of surfactants. Sodium caseinate formed the thickest coatings, but these were very thin in every case, which led to there being no predicted relevant effect on the gas exchanges of the fruit. The cell viability in the films was good during film drying, especially in the case of protein films; however, it decreased after storage.The authors are grateful to the Spanish Government for the financial support through project RTA2012-00067-0O2 and to the Conselleria d'Educacio of the Generalitat Valenciana, (Spain) for A. Marin's PhD grant (VALi+d 2013). The authors are also thankful to IRTA group, headed by Dra. Neus Teixido, for their assistance in the microbiological study.Marín-Gozalbo, A.; Atarés Huerta, LM.; Cháfer Nácher, MT.; Chiralt, A. (2017). Properties of biopolymer dispersions and films used as carriers of the biocontrol agent Candida sake CPA-1. LWT - Food Science and Technology. 79:60-69. https://doi.org/10.1016/j.lwt.2017.01.024S60697

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

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

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