Sajid Latif

Amino acid composition, antinutrients and allergens in the peanut protein fraction obtained by an aqueous enzymatic process

Enzyme-assisted aqueous extraction (EAE) of peanut kernel was used to extract oil and protein. The aqueous fraction (AF) obtained by EAE had a better essential amino acid profile than the residues obtained by solvent extraction (Rs) and cold pressing (Rc). No major difference in the trypsin inhibitor activity among AF, Rs and Rc was observed; however, the trypsin inhibitor activity was drastically reduced in the residue obtained after EAE. AF was subjected to MALDI-TOF/MS, revealing it to be rich in peptides (107) with molecular masses from m/z 700 to 2369Da. AF had an extremely low phytate content and was rich in peptides, which could be used as a food supplement. ESI-MS/MS data were used for the identification of major peanut allergens, viz., Ara h1, h3, h6-8. Their allergenic potential needs to be established.

Compositional and functional dynamics of dried papaya as affected by storage time and packaging material.

Papaya has been identified as a valuable source of nutrients and antioxidants, which are beneficial for human health. To preserve the nutritional properties after drying, appropriate storage specifications should be considered. This study aimed to investigate the quality and stability of air-dried papaya in terms of quality dynamics and behavior of bio-active compounds during storage for up to 9 months in two packaging materials: aluminum laminated polyethylene and polyamide/polyethylene. Samples with moisture content (MC) of 0.1328 g g(-1) and water activity (aw) of 0.5 were stored at 30 °C and relative humidity (RH) of 40-50%. The MC, aw, degree of browning (DB) and 5-hydroxymethylfurfural (HMF) content were found to notably increase as storage progressed. On the contrary, there was a significant decrease in antioxidant capacity (DPPH, FRAP and ABTS), total phenolic (TP) and ascorbic acid (AA) contents. Packaging in aluminum laminated polyethylene under ambient conditions was found to better preserve bio-active compounds and retard increases in MC, aw and DB, when compared to polyamide/polyethylene.

Effect of self-purging pyrolysis on yield of biochar from maize cobs, husks and leaves.

In this study, biochar was produced from maize residues (cobs, husks, leaves) in a lab-scale pyrolysis reactor without using a purging gas. The physicochemical properties of biomass and biochar were analysed. Box-Behnken design was used to optimise operational conditions for biochar yields. Multivariate correlations of biochar yields were established using reduced quadratic models with R(2)=0.9949, 0.9801 and 0.9876 for cobs, husks and leaves, respectively. Biochar yields were negatively correlated with the temperature, which was significantly influenced by the exothermic reactions during the pyrolysis of maize residues. The heating rate was found to have the least effect on biochar yields. Under optimal conditions, the maximum biochar yields from cobs, husks and leaves were 33.42, 30.69 and 37.91%, respectively. The highest biochar yield from maize leaves was obtained at a temperature of 300°C, a heating rate of 15°C/min and a holding time of 30min.

Increasing the loading rate of continuous stirred tank reactor for coffee husk and pulp: Effect of trace elements supplement

In this study, the anaerobic performance and stability of coffee husk and pulp with and without trace element (TE) supplement was investigated, using 20 L mesophilic continuous stirred tank reactors for 140 days of experiment (DOE). The TE was cocktail of trace metals composed of Fe, Ni, Zn, Co, Mn, Mo, Se W and B. The organic loading rate (OLR) was increased stepwise from 2.5 (HRT = 40 d) to 6.0 kg VS m−3 d− 1(HRT = 16.7 d). The highest methane productivity from pulp with and without TE was 1.272 and 0.965 m3 m−3 d−1 at an OLR of 6.0 and 5.0 kg VS m−3 d−1; while the husks performed 0.895 and 0.795 m3 m−3 d−1 respectively, both at an OLR of 6.0 kg VS m−3 d−1. The specific methane yield (SMY) of pulp (at OLR = 5 kg VS m−3 d−1) with and without TEs was 217.9 ± 4.7 and 193.1 ± 8.2 L kg−1 VS; while husk yielded 149.2 ± 6.0 and 132.5 ± 4.9 L kg−1 VS, respectively. The effect of TEs on SMY was statistically significant (p < 001) at higher OLRs (5.0 ‐ 6.0 kg VS m−3 d−1). The TEs improved the anaerobic stability through an optimum alkalinity ratio (VFA/TIC < 0.3) and suppressed the accumulation of volatile fatty acids. Mono digestion of husks and pulp are prone to lack Mo, Zn, Ni and Fe in long‐term anaerobic fermentation. Further studies on co‐digestion of husk/pulp with animal manure and dry fermentation helps to efficiently use this biomass resource.

Characterisation of biochar from maize residues produced in a self-purging pyrolysis reactor

Response surface methodology was used to optimise pyrolysis conditions to produce biochar from maize residues (cobs, husks, leaves and stalks). The aim was to obtain biochar with good potential as an additive for composting. Mathematical models were developed to explain the experimental responses of volatile matter content (VM), ash content (AC), pH and electrical conductivity (EC) to the operating parameters such as temperature, heating rate and holding time. The temperature had the most significant influence on biochar properties. AC, pH and EC significantly increased (p < 0.05) with increasing temperature, while the VM decreased. The holding time showed less effect on the responses, while the heating rate had insubstantial effect. Under the optimal conditions, the husk and leaf biochar had higher AC (11.42 and 26.55%), pH (10.96 and 11.51), and EC (12.37 and 6.79 mS/cm), but lower VM (7.38 and 8.39%) than those of cob and stalk biochar.