Search

Summary: Starch nanocrystals (SNCs) have emerged as promising biodegradable nanomaterial for the enhancement of biopolymer films' properties. Nevertheless, using SNCs alone is difficult due to restricted capacity for nanocrystal integration within the film's matrix. The objective of this study was to enhance the properties of biopolymer films using waxy corn starch nanocrystals supplemented with stearic acid. Cassava starch films containing varying proportions of SNCs (0–20 wt.% starch) and steric acid (2%) were prepared and characterised. The inclusion of stearic acid substantially improved SNC integration from 5% to 15%, yielding nanocomposite films with better tensile strength, thermal stability and barrier properties than those prepared with native starch or starch‐fatty acid alone. The improvement in film properties was attributed to V‐amylose complexes formation, increased crystallinity and hydrophobicity. Microscopy images revealed homogenous film surfaces, depicting greater nanocrystal dispersibility. The supplementation of lipid additives offers a valuable strategy to improve the integration of SNCs in film matrices. [ABSTRACT FROM AUTHOR]

The microstructure, elemental distribution and rheological behavior of two varieties of gari and their doughs (eba) were investigated. SEM analysis revealed a concave structure with fibre-strands, which were altered after processing to eba. Gari nanostructures which were analyzed with TEM were not affected when processed to eba. SEM-EDX microanalysis revealed the presence of magnesium, potassium, calcium, manganese, iron, and cobalt for both varieties, which were altered after processing. Rheological analysis revealed increases in storage modulus, with concomitant loss factor for both varieties. Their viscosity decreased with increasing shear rate. GC-MS analysis revealed the presence of sugar, fatty acids, and steroids in both varieties, which were also affected after processing. Both varieties showed significant free radical scavenging activity which was not affected after processing. These results indicate that the conclave microstructure, elements and phytochemicals of both gari varieties are altered after processing to eba, with their nanostructure and antioxidant activity unaltered. [ABSTRACT FROM AUTHOR]

BACKGROUND An increased rate of high blood pressure has led to critical human hypertensive conditions in most nations. In the present study, bambara protein hydrolysates ( BPHs) obtained using three different proteases (alcalase, trypsin and pepsin) and their peptide fractions (molecular weight: 10, 5, 3 and 1 kDa) were investigated for antihypertensive and antioxidant activities. RESULTS Alcalase hydrolysate contained the highest amount of low molecular weight ( LMW) peptides compared to pepsin and trypsin hydrolysates. LMW peptides fractions (<1 kDa) exhibited the highest inhibitory activity against angiotensin-converting enzyme ( ACE) for all the enzymes hydrolysates. For renin inhibition, alcalase hydrolysate showed the highest inhibition at 59% compared to other hydrolysates and their corresponding membrane fractions. The antioxidant power of bambara protein hydrolysates and peptide fractions was evaluated through the inhibition of linoleic acid peroxidation and ABTS scavenging activity. Among the hydrolysates, alcalase exhibited the highest inhibition of linoleic acid oxidation. Furthermore, all BPHs were able to scavenge ABTS•+ to a three-fold greater extent compared to the isolate. CONCLUSION BPH and LMW peptide fractions could potentially serve as useful ingredients in the formulation of functional foods and nutraceuticals against high blood pressure and oxidative stress. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Science (John Wiley & Sons, Inc.) is the property of John Wiley & Sons, Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND Vitamin A deficiency is a major public health problem in sub-Saharan Africa. Amahewu is a popular southern African lactic acid fermented non-alcoholic maize-based beverage, which is deficient in vitamin A. In this study, provitamin A retention and sensory acceptability of amahewu processed using provitamin A-biofortified maize and three types of inoculums during fermentation (malted maize, wheat bran and Lactobacillus starter culture) were investigated. RESULTS The total provitamin A content of amahewu samples, estimated as β-carotene, β-cryptoxanthin and α-carotene content, ranged from 3.3 to 3.8 g kg−1 (dry weight). Provitamin A was substantially retained (79- 90% β-carotene equivalent) in amahewu after fermentation. Amahewu samples prepared with added starter cultures had the lowest retention of provitamin A. Consumers (approx. 69%) liked provitamin A-biofortified amahewu either moderately or very much. Principal component analysis of amahewu sensory data showed that 71% of variation was due to maize types and 18% of variation could be due to the inoculum used during fermentation. Amahewu samples prepared using provitamin A-biofortified maize were slightly more liked (mean score: 7.0 ± 1.2) compared to those of white maize reference samples. The use of starter culture combined with either malted maize or wheat bran as inoculum during fermentation improved the taste and aroma of amahewu and hence its acceptability. CONCLUSION Provitamin A is substantially retained in amahewu after fermentation. The slightly high acceptability of amahewu prepared using provitamin A-biofortified maize compared to that of white maize thus suggests that fermented product like amahewu can potentially be used to deliver provitamin A to vulnerable individuals. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]