The production of hydrolysates from industrially defatted rice bran and its surface image changes during extraction

BACKGROUND This research employed mild-subcritical alkaline water extraction (SAW) technique to overcome the difficulty of active compounds extractability from an industrially defatted rice bran (IDRB). Mild-SAW (pH 9.5, 130 °C, 120 min) treatment, followed by enzymatic hydrolysis (Protease G6) were applied to produce rice bran hydrolysate (RBH). Response surface methodology was used to identify proteolysis conditions for maximizing protein content and ABTS radical scavenging activity (ABTS-RSA). The microstructural changes during the extraction occurring in the IDRB were monitored. The selected RBH was characterised for protein recovery, yield, antioxidant activities, phenolic profile and hydroxymethylfufural (HMF) content. RESULTS Optimal proteolysis conditions were at 20 mL kg-1 IDRB (E/S) for 6 h. Under these conditions, the yield, ABTS-RSA, Ferric reducing antioxidant power and the total phenolic content of the RBH were 46.1%, 294.22 μmol trolox g-1, 57.72 μmol FeSO4 g-1, and 22.73 mg gallic acid g-1, respectively, with relatively low HMF level (0.21 mg g-1). The protein recovery was 4.8 times greater than the recovery obtained by conventional alkaline extraction. Its major phenolic compounds were p-coumaric and ferulic acids. The microstructural changes of IDRB confirmed that the mild-SAW/Protease G6 process enhanced the release of active compounds. CONCLUSION The process of mild-SAW followed by proteolysis promotes the release of active compounds from IDRB

Effects of extended mixing processes on fresh, hardened and durable properties of cement systems incorporating fly ash.

Specifications that correspond with system performance may guarantee the addition of value. Most specifications for ready-mixed concrete address limits on discharge time and truck-drum revolution counts. These limits have been developed for conventional concrete. As the uses of supplementary cementing materials (SCMs) become ubiquitous, it is important to determine whether these specifications are applicable to SCMs, that is, systems containing fly ash. This paper presents results of the effects of mixing time and mixer revolution counts on characteristics of lab-made pastes and mortars containing 20% and 50% fly ash. Their characteristics assessed include time-variant ion concentrations, setting time, flow, compressive strength, porosity, and apparent chloride diffusivity coefficient. Results indicate that with increasing mixing time and mixer revolution counts, mixtures with a replacement of fly ash exhibit improved both fresh and hardened characteristics. When mixed for 60 min or 25,505 revolution count, the 28-day compressive strengths of mixtures containing 20% and 50% fly ash are 50% to 100% higher than the neat cement. Fly ash is suggested to adopt in the extended mixing processes of cement systems

Effects of pasteurization and storage time on watermelon juice quality enriched with L-citrulline

Watermelon juice has gained increasing popularity among consumers as a rich natural source of functional compounds such as lycopene and L-citrulline. This amino acid is an excellent candidate to reduce muscle soreness. Watermelon juice enriched with L-citrulline is presented as an industry opportunity for the sport drink sector. However, the application of conventional thermal pasteurization can degrade those functional compounds. Effects of pasteurization at 80°C for 40 s (PW-40 s) or 90 s (PW-90 s) and storage (4°C for 30 days) on watermelon juice enriched with Lcitrulline was studied. Before pasteurization, initial lycopene content was 14.65±0.30 mg kg-1, reducing to 10.50±0.06 in PW-40 s and 10.10±0.08 mg kg-1 in PW-90 s after 30 days. Initial enriched L-citrulline content was 15.68±0.05 g L-1 that decreased to 12.38±0.03 in PW-40 s and 12.04±0.09 g kg-1 in PW-90 s treatment after 30 days of storage. Pathogenic bacteria (Salmonella spp., Listeria monocytogenes and Escherichia coli) were not detected during storage. However, mesophilic growth was high, reaching 7.5 log cfu mL-1 in PW-40 s and 6.5 log cfu mL-1 in PW-90 s. The appearance limited the shelf life to 25 days for PW-40 s and only 15 days for PW-90 s. The use of higher temperatures of pasteurization is necessary to obtain a safe watermelon juice, but this needs to be balanced with reduced treatment times to maintain functional and sensory parameters which are easily thermo-degraded