Amit Arora

Bioactives from fruit processing wastes: Green approaches to valuable chemicals

Fruit processing industries contribute more than 0.5billion tonnes of waste worldwide. The global availability of this feedstock and its untapped potential has encouraged researchers to perform detailed studies on value-addition potential of fruit processing waste (FPW). Compared to general food or other biomass derived waste, FPW are found to be selective and concentrated in nature. The peels, pomace and seed fractions of FPW could potentially be a good feedstock for recovery of bioactive compounds such as pectin, lipids, flavonoids, dietary fibres etc. A novel bio-refinery approach would aim to produce a wider range of valuable chemicals from FPW. The wastes from majority of the extraction processes may further be used as renewable sources for production of biofuels. The literature on value addition to fruit derived waste is diverse. This paper presents a review of fruit waste derived bioactives. The financial challenges encountered in existing methods are also discussed.

High xylan recovery using two stage alkali pre-treatment process from high lignin biomass and its valorisation to xylooligosaccharides of low degree of polymerisation

In the present work, xylan from arecanut husk was extracted using 2 stage alkaline pretreatment process. In first step, biomass was incubated in alkali at different temperatures (25 °C, 50 °C and 65 °C), alkali concentrations (5%, 10%, 15% and 20% w/v), and incubation periods (8 h, 16 h and 24 h) and evaluated for xylan recovery. It was observed that 40-52% of available xylan could be recovered using 10% alkali when incubated for 8-24 h at 65 °C. Subsequently, the alkali pretreatment operating conditions which provided good xylan recovery were processed further using hydrothermal treatment to extract more xylan. For maximum xylan recovery (>90%), best operating conditions were identified when biomass was treated under hydrothermal treatment (1, 1.5 and 2 h) with varying incubation periods (8, 16, 24 h) and alkali concentrations (5%, 10%) using full factorial design. Incubating arecanut husk with 10% w/v NaOH, at 65 °C for a period of 8 h, followed by hydrothermal treatment at 121 °C for 1 h helped recover >94% xylan. In the next step, enzymatic hydrolysis process was optimized to recover maximum XOS (Optimized condition: 50 °C, pH 4 and 10 U enzyme dose). The hydrolysate comprised of xylobiose: 25.0 ± 1.2 g/100 g xylan (∼71% of XOS), xylotriose: 9.2 ± 0.65 g/100 g xylan (26.2% of XOS) and xylotetrose: 0.9 ± 0.04 g/100 g xylan (2% of XOS). The developed process enables to reduce alkali consumption for high recovery of xylan from biomass with relatively higher lignin content for its valorisation into a potential prebiotic oligosaccharide.

Effect Of Drying Methods And Extraction Time-Temperature Regime On Mango Kernel Lipids

In this study, effect of drying method and time temperature regime of extraction on quality of mango kernel lipid was evaluated. Hot air drying required drying of seeds for long intervals and exposure to higher temperature, where as microwave drying was found to be quick due to heating induced at the molecular level. The drying time under optimized conditions for microwave was reduced by 34 folds when compared with hot air drying. Parameters including drying temperature, extraction time, lipid yield and fatty acid profile were evaluated. The study shows that modification of extraction method for lower temperature and lesser time does not alter the quality and quantity of lipids from mango kernel (10.8%). Structural changes induced due to drying were studied using scanning electron microscopy. Statistical analysis showed that drying conditions and extraction conditions affected the lipid yield. The further comparison between two methods was done in terms of fatty acid profiles and oxidative stability. The stability of lipid was estimated by measuring the ratio of linoleic acid to palmitic acid for all extraction conditions. The ratio of C18:2/C16 was similar for microwave irradiation when compared to hot air dried samples (1.0 1.2). It was concluded that mild microwave power level (180W) helps in quick drying of kernels. The structure was found to be intact with minimal damage to starch granules. Lower microwave power level helped in retention of the lipid yield and quality while higher microwave power levels significantly affected the unsaturated fatty acids. *Corresponding author: Amit Arora, Indian Institute of Technology, Powai, Maharashtra, India, Tel: +91(22)-2576-7293; E-mail: aarora@iitb.ac.in Received Date: February 13, 2016 Accepted Date: May 11, 2016 Published Date: May 16, 2016

An integrated green biorefinery approach towards simultaneous recovery of pectin and polyphenols coupled with bioethanol production from waste pomegranate peels

An integrated biorefinery, incorporating hydrothermal processing of waste pomegranate peels (WPP), was proposed for the acid and organic solvent-free simultaneous recovery of pectin and phenolics with bioethanol production. The hydrothermal treatment (HT) was optimized using Box-Behnken design and the maximum recovery of pectin (18.8-20.9%) and phenolics (10.6-11.8%) were obtained by hydrothermal treatment at 115 °C for 40 min with a liquid-solid ratio of 10. The WPP pectin was characterized by IR, 1H NMR, and TGA which showed close similarity to commercial pectin. Depending on WPP cultivar type the degree of esterification, galacturonic acid content and molecular weight of pectin were in the range of 68-74%, 71-72%, and 131,137-141,538 Da, respectively. The recovered phenolics contained 57-60% punicalagin. Enzyme digestibility of WPP improved using HT with 177 g glucose produced per kg dry mass which was fermented to obtain 80 g ethanol with 88% of theoretical yield.

Time-dependent nonlinear analysis of gyro-TWT amplifier

In the present paper, the beam-wave interaction behavior in the gyro-TWT amplifier has been studied using time dependent nonlinear single-mode analysis. The time dependent equations of motion which describes the interaction of the electrons with the RF wave are solved self-consistently for the performance evaluation of a typically selected fundamental mode 35GHz gyro-TWT amplifier operating at TE01 mode. The results from nonlinear analysis shows that the present gyro-TWT produces a stable output power of 165kW for 1% velocity spread at 35GHz, with ~42dB gain, 22% efficiency for a 72kV, 10A gyrating electron beam. The analytically obtained values of RF output power and gain are found to be in agreement with the available published results within ~10%.