Physical and nutritional properties of black monkey orange fruit and seeds: A preliminary analysis for food processing.

Strychnos madagascariensis is an underutilized South African fruit-bearing tree, with the pulp being the primary consumable component. However, the seeds hold the potential as a food source due to their high nutrient composition. The aim of this study was to determine the physical properties of S. madagascariensis fruit and seeds to aid in food processing equipment development. Fruit physical properties were determined at four progressive ripening stages, as well as the seed physical properties and mineral composition. The pulp contributed the most towards fruit composition across stages of ripeness (c 50%), followed by the rind (c 30%) and seeds (c 20%). Furthermore, significant variations in seed physical properties were observed at progressive maturity stages. The seeds showed significantly greater mineral compositions in unripe-green fruit in comparison to fruit at progressive ripening stages. The data provided may serve as a basis for the development of processing procedures and equipment and suggests that seeds of unripe-green fruit hold greater nutritional benefits.

Inducing PLA/starch compatibility through butyl-etherification of waxy and high amylose starch.

In this study, waxy and high amylose starches were modified through butyl-etherification to facilitate compatibility with polylactide (PLA). Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and wettability tests showed that hydrophobic butyl-etherified waxy and high amylose starches were obtained with degree of substitution values of 2.0 and 2.1, respectively. Differential scanning calorimetry, tensile testing, and scanning electron microscopy (SEM) demonstrated improved PLA/starch compatibility for both waxy and high amylose starch after butyl-etherification. The PLA/butyl-etherified waxy and high amylose starch composite films had higher tensile strength and elongation at break compared to PLA/non-butyl-etherified composite films. The morphological study using SEM showed that PLA/butyl-etherified waxy starch composites had a more homogenous microstructure compared to PLA/butyl-etherified high amylose starch composites. Thermogravimetric analysis showed that PLA/starch composite thermal stability decreased with starch butyl-etherification for both waxy and high amylose starches. This study mainly demonstrates that PLA/starch compatibility can be improved through starch butyl-etherification.

Occurrence of amylose-lipid complexes in teff and maize starch biphasic pastes.

The occurrence of amylose-lipid complexes was determined in maize and teff starch biphasic pastes i.e. peak viscosity pastes at short and prolonged pasting times. Maize and teff starches were pasted for 11.5 and 130 min with or without added stearic acid followed by thermo-stable alpha-amylase hydrolysis in a rapid visco-analyzer. X-ray diffraction analysis of pastes before and residues after hydrolysis showed crystalline V-amylose diffraction patterns for the starches pasted for a prolonged time with added stearic acid while less distinct V-amylose patterns with non-complexed stearic acid peaks were observed with a short pasting time. Differential scanning calorimetry of pastes before and residues after paste hydrolysis showed that Type I amylose-lipid complexes were formed after pasting for the short duration with added stearic acid, while Type II complexes are formed after pasting for the prolonged time. The present research provides evidence that amylose-lipid complexes play an important role in starch biphasic pasting.