In this study, aqueous extraction of phenolic compounds from jamun (Syzygium cumini L.) seed was undertaken. The effects of various parameters such as extraction temperature (34.8-85.2°C), extraction time (49.8-100.2 min), and liquid-to-solid ratio (9.8-60.2 mL/g) on the extraction yield, extract purity (i.e., total polyphenol content), and its antioxidant activities (1,1-diphenyl-2-picrlthydrazyl free radical scavenging assay and ferric reducing antioxidant power) were investigated. Response surface methodology was used to optimize the extraction conditions. The optimum extraction conditions (49.2°C, 89.4 min, and 51.6:1 mL/g) produced an extract with 17.3% extraction yield, high total polyphenol content (415 mg gallic acid equivalent/g dried extract) and significant antioxidant activity (IC 50 : 35.4 ± 0.7 µg/mL). The high-performance liquid chromatography analysis of seed extract revealed the presence of gallic acid (90.8 mg/g dried extract), ellagic acid (36 mg/g dried extract), caffeic acid (26.07 mg/g dried extract), p-coumaric acid (0.26 mg/g dried extract), catechin (9.05 mg/g dried extract), epicatechin (0.42 mg/g dried extract), and quercetin (1.54 mg/g dried extract). Tannic acid (188.5 mg/g dried extract) was also identified as a major phenolic compound. The extraction kinetics was also studied and experimental data were fitted to four kinetic models such as first-order model, second-order model, Peleg's model, and Minchev and Minkov model, to evaluate their applicability.

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The aim of this study was to analyze flux decline behavior during ultrafiltration (UF) of jamun (Syzygium cumini [L.]) seed extract using Harmia's model and Koltuniewicz's surface‐renewal model. The effects of different transmembrane pressure and stirrer speed on the membrane fouling, permeate flux, and permeate quality were studied. Analysis of the results revealed that UF of seed extract was controlled by a cake filtration mechanism. Phenolic compounds in UF clarified and nanofiltration concentrated extract were identified and quantified using high‐performance liquid chromatography. Storage stability of quality parameters (total phenolic content (TPC), total flavonoid content (TFC), color, and clarity) of jamun seed extract and nanofiltration concentrated extract were studied at 4, 27, and 37 °C for 30 days. A first‐order kinetic model was successfully used to evaluate the degradation of TPC and TFC during storage. Three models (Arrhenius, Eyring, and Ball) were shown to be suitable to describe the temperature dependence of the deterioration rate constant of TPC and TFC. Experimental results confirmed that membrane processing of jamun seed extract enhanced the storage stability of all the quality parameters tested. The estimated model parameters might be useful for design and scale‐up of the system and to identify the appropriate storage conditions for industrial processing.

Electric field-enhanced separation of polyethylene glycol (PEG) from an aqueous electrolyte solution of bovine serum albumin has been carried out. Experimental results show a significant improvement in both permeate flux and PEG transmission with the application of a suitable d.c. electric field. A mass transfer model based on film theory is proposed for prediction of permeate flux and observed retention of PEG. The model uses single parameter, namely real retention (R r2 ) of the PEG which is evaluated by optimizing the experimental values of steady state permeate flux and permeate concentration. Model predictions are in good agreement with the experimental data.