Isolation, composition, morphological and pasting properties of starches from rice cultivars grown in Nigeria

Enhancing functional properties of rice starches through hydroxypropylation for development of reduced-fat white sauces

Present study investigated the preparation of commonly used white sauce with 50 % less added fat by using 10 % hydroypropylated Irri and Basmati rice starches in the formulation. The sauces incorporated with hydroxypropylated starches exhibited significantly lower gelatinization temperature and time, while the change in maximum viscosity was insignificant. Significantly improved stability at ambient, refrigeration, and freezing temperatures of reduced-fat white sauces was observed whereas change in the taste was insignificant. Basmati hydroxypropylated starch containing white sauce significantly mimicked the sensory properties of full-fat sauces. The hydroxypropyl groups were found to be 1.06 % and 1.16 % for Basmati and Irri hydroxypropylated starches, respectively. These values fall below the specified limit set by the Food and Drug Administration for the food grade hydroxypropylated starches. Significant improvements in peak viscosity, swelling power, solubility, percent transmittance, and water retention capacity were observed after the chemical modification of both rice varieties.

Characterization of starch extracted from seeds of Cycas revoluta

Introduction

Starch is major component in the big seeds of Cycas revoluta, however the characteristics of Cycas revoluta remain unknown.

Methods

In this study, the physicochemical and structural properties of two starch samples extracted from Cycad revoluta seeds were systematically investigated, using various techniques.

Results

The amylose contents of the two samples were 34.3 % and 35.5%, respectively. The spherical-truncated shaped starch granules possessed A-type crystallinity, and had an average diameter less than 15 μm. Compared to most commonly consumed cereal and potato starch, Cycad revoluta starch showed distinctive characteristics. For physicochemical properties, in the process of gelatinization, the Cycad revoluta starch showed similar viscosity profile to starches of some potato varieties, but Cycad revoluta starch had higher gelatinization temperature. Upon cooling, Cycad revoluta starch formed harder gels than rice starch. For structure, the molecular weight (indexed by Mw, Mn and Rz values), branching degree and the branch chain length distribution were determined.

Discussion

The results suggested that Cycad revoluta starch were different in structure from the main-stream starches. Notable differences in some starch traits between the two samples were recorded, which could be attributed to environmental factors. In general, this study provides useful information on the utilization of Cycad revoluta starch in both food and non-food industries.

Evaluation and Multivariate Analysis of Cowpea [Vigna unguiculata (L.) Walp] Germplasm for Selected Nutrients—Mining for Nutri-Dense Accessions

A total of 120 highly diverse cowpea [Vigna unguiculata (L.) Walp] genotypes, including indigenous and exotic lines, were evaluated for different biochemical traits using AOAC official methods of analysis and other standard methods. The results exhibited wide variability in the content of proteins (ranging from 19.4 to 27.9%), starch (from 27.5 to 42.7 g 100 g−1), amylose (from 9.65 to 21.7 g 100 g−1), TDF (from 13.7 to 21.1 g 100 g−1), and TSS (from 1.30 to 8.73 g 100 g−1). The concentration of anti-nutritional compounds like phenols and phytic acid ranged from 0.026 to 0.832 g 100 g−1 and 0.690 to 1.88 g 100 g−1, respectively. The correlation coefficient between the traits was calculated to understand the inter-trait relationship. Multivariate analysis (PCA and HCA) was performed to identify the major traits contributing to variability and group accessions with a similar profile. The first three principal components, i.e., PC1, PC2, and PC3, contributed to 62.7% of the variation, where maximum loadings were from starch, followed by protein, phytic acid, and dietary fiber. HCA formed six distinct clusters at a squared Euclidean distance of 5. Accessions in cluster I had high TDF and low TSS content, while cluster II was characterized by low amylose content. Accessions in cluster III had high starch, low protein, and phytic acid, whereas accessions in cluster IV contained high TSS, phenol, and low phytic acid. Cluster V was characterized by high protein, phytic acid, TSS, and phenol content and low starch content, and cluster VI had a high amount of amylose and low phenol content. Some nutri-dense accessions were identified from the above-mentioned clusters, such as EC170579 and EC201086 with high protein (>27%), TSS, amylose, and TDF content. These compositions are promising to provide practical support for developing high-value food and feed varieties using effective breeding strategies with a higher economic value.

Analysing the structure and glass transition behaviour of silks for archaeology and conservation

Silk is an iconic material in many cultures. Silk archaeology and conservation is affected by silk production technology as well as subsequent environmental effects such as humidity, temperature, UV radiation and ageing. The complex interactions and various effects on silk materials affect the practical use of silk, for example, in the conservation of ancient manuscripts. This study examines the various influences of silk provenance and processing, adhesive coatings and chemical treatments as well as natural and artificial ageing of the silk material. We use infrared spectroscopy (FTIR) and dynamic mechanical thermal analysis to investigate the glass transition behaviours in a range of archaeological and control silk samples. This allows us to establish structural differences in century-old museum silks and predict the effects of silk ageing and degradation.