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The present study has focused on the extraction and utilization of antioxidant compounds from the agricultural produce Zingiber officinale for its sustainable use in terms of stabilizing food from oxidation. Two extraction methods, traditional soxhlet and green supercritical CO2 (SC-CO2), were used to compare yields of antioxidant (6-gingerol) rich extracts. For the SC-CO2 method, operating parameters including pressure (10000-20000 kPa), temperature (30- 40°C) and CO2 flow rate (5-20 g/min.) were optimized to get maximum recovery of [6]-gingerol rich extracts. The results of the extraction study revealed that ginger extract collected after soxhlet extraction (GE1) gives more yield (3.85%) than the extract (2.41%) collected after SC-CO2 extraction (GE2) at an optimum condition of 20000 kPa pressure, 40°C temperature and 20 g/min. flow rate. Contrarily, the yield of [6]-gingerol was found to be greater in GE2 (389 mg/g) than GE1. Total phenol (TPC) and flavonoid (TFC) content of GE1 and GE2 were measured against equivalent concentrations of gallic acid and quercetin. TPC and TFC of GE1 show slightly higher values (38.50 mg GAE/g, 5.62 mg QE/g) than GE2. At the concentration of 3000 μg/mL, DPPH percent inhibition activity of GE1 was again higher (up to 94%) than GE2 (up to 82%). Stability study result of both GE1 and GE2 revealed on the basis of antioxidant indices, showed desirable antioxidant index by stabilizing all three experimented oils and also found to be comparable with synthetic antioxidants (BHA, BHT). Therefore, it could be concluded that [6]-gingerol rich extracts from the SC-CO2 method have comparable phenol flavonoid, antioxidant and stability potential as those found in ginger extracts from the traditional soxhlet method.

Four leafy vegetable species, spinach (Spinacia oleracea), amaranthus (Amaranthus viridis), fenu-greek (Trigonella foenum-graecum) and bathua (Chenopodium album), were extracted with three different solvents (80% ethanol, 80% acetone and water) for maximum recovery of phenol and antioxidant compounds in the extract. The results of extraction were compared with extraction from moringa (Moringa oleifera) leaves that is known as a very rich source of antioxidants. The study showed that, it is very difficult to justify a single solvent for extraction of antioxidant compounds from different plants. Results from different solvents used for extracting the bioactive compounds mostly depend on the type of compound extracted (polar/medium polar/non-polar) present in leafy matrices. Here, 80% acetone extract showed highest total phenol content in moringa leaves but the overall antioxidant activity in the leaves of four vegetables was observed to be better after extraction with 80% ethanol. Nevertheless, in most assays, independent of solvent used for extraction, the moringa leaves were the richest source of polyphenols and antioxidants.

Adulteration is a crucial issue being faced by essential oil and allied industries, especially for high‐value essential oil such as agarwood oil. The recommended analysis in trading essential oils involves visual inspection, olfactory analysis, physico‐chemical characterization and gas chromatography coupled with mass spectroscopy (GC–MS). However, some subtle high‐boiler adulterants like vegetable oils and synthetic polymers go unnoticed via these analyses leading to the penetration of adulterated essential oil in the market. In the current study, the thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTGA) were utilized and suggested as a rapid, convenient and precise technique for the detection of high‐boiler adulterants in essential oils using the most expensive agarwood oil as a case study. The TGA pattern of pure samples reveals single‐stage volatilization (agarwood oil: 110–260°C, castor oil: 340–500°C, coconut oil: 330–450°C and polyethylene glycol‐400: 260–390°C), whereas the adulterated sample exhibits two‐stage volatilization in both lower‐ and higher‐temperature zone owing to the presence of agarwood oil and high‐boiler adulterant. The DTGA of pure agarwood oil shows only one point of major weight loss, whereas that of the adulterated sample shows two points of major weight loss corresponding to both oil and adulterant. Different percentages of adulterants (5%, 10%, 30% and 50%) have been quantified using TGA and DTGA with the highest accuracy. Further, the method optimization study was conducted to determine the minimum time required for adulterated sample analysis with precise accuracy. TGA can be proposed as a handy and efficient tool for the quality control analysis of essential oils. [ABSTRACT FROM AUTHOR]

The present study was to characterize the lipid profile of five black soybean (BS) produced in Indo‐Himalayan regions. Among seven fatty acids (FAs), methyl linoleate and cis‐9‐oleic acid methyl ester were maximum. Unsaturated/saturated fatty acid ratio was highest (6.10%) in BSALB (big spherical shape seed). Unsaponifiable matters and tocopherols were also higher (3.09% and 1305 μg/kg, respectively) in BSALB, while β‐carotene was improved in BSALS (small oval‐shaped seed). Flavor analysis reported 46 compounds in the oil, which were maximum in BSALS. There was significant difference (p < 0.02) in the flavor components. Crop cycle temperature is inversely correlated with major lipid constituents. The results suggest that the BS seeds produced comparatively in high‐altitude regions retain the maximum lipid antioxidants and flavor compounds. Presence of these phytoconstituents may be explored to utilize black soybean in flavor and nutraceutical industries to boost the application of this underutilized crop. [ABSTRACT FROM AUTHOR]

Biodiesel, fatty acid methyl ester produced by the transesterification of vegetable oil with methanol, is a promising alternative to petroleum-based diesel fuel. In the present study, the methanolysis of high free fatty acid (FFA) Jatropha curcas oil in a transesterification reaction using K2CO3 /CaO solid base catalyst was studied. The various reaction parameters in the transesterification reaction were also discussed. The catalyst was characterized by means of Fourier transform infrared, X-ray diffraction, temperature programmed desorption of CO2 , scanning electron microscopy, particle size analyzer, true density, and surface area analyzer. The optimum conversion of jatropha oil was 92% when the transesterification reaction was carried out at 70 °C with 10:1 molar ratio of methanol to oil at reaction time of 3 h and catalyst amount of 6 wt%. The efficiency of catalysts in the methanolysis of jatropha oil was also investigated. [ABSTRACT FROM AUTHOR]