Rohit Upadhyay

Classification of Sunflower Oil Blends Stabilized by Oleoresin Rosemary (Rosmarinus officinalis L.) Using Multivariate Kinetic Approach.

The sunflower oil-oleoresin rosemary (Rosmarinus officinalis L.) blends (SORB) at 9 different concentrations (200 to 2000 mg/kg), sunflower oil-tertiary butyl hydroquinone (SOTBHQ ) at 200 mg/kg and control (without preservatives) (SO control ) were oxidized using Rancimat (temperature: 100 to 130 °C; airflow rate: 20 L/h). The oxidative stability of blends was expressed using induction period (IP), oil stability index and photochemiluminescence assay. The linear regression models were generated by plotting ln IP with temperature to estimate the shelf life at 20 °C (SL20 ; R(2) > 0.90). Principal component analysis (PCA) and hierarchical cluster analysis (HCA) was used to classify the oil blends depending upon the oxidative stability and kinetic parameters. The Arrhenius equation adequately described the temperature-dependent kinetics (R(2) > 0.90, P < 0.05) and kinetic parameters viz. activation energies, activation enthalpies, and entropies were calculated in the range of 92.07 to 100.50 kJ/mol, 88.85 to 97.28 kJ/mol, -33.33 to -1.13 J/mol K, respectively. Using PCA, a satisfactory discrimination was noted among SORB, SOTBHQ , and SOcontrol samples. HCA classified the oil blends into 3 different clusters (I, II, and III) where SORB1200 and SORB1500 were grouped together in close proximity with SOTBHQ indicating the comparable oxidative stability. The SL20 was estimated to be 3790, 6974, and 4179 h for SO control, SOTBHQ, and SORB1500, respectively. The multivariate kinetic approach effectively screened SORB1500 as the best blend conferring the highest oxidative stability to sunflower oil. This approach can be adopted for quick and reliable estimation of the oxidative stability of oil samples.

Electronic nose guided determination of frying disposal time of sunflower oil using fuzzy logic analysis

An electronic nose (e-nose), having 18 metal oxide semiconductor (MOS) sensors, guided determination of frying disposal time of sunflower oil is reported. The ranking and screening of MOS sensors, specific for volatile organic compounds, was performed using fuzzy logic. A correlation was examined between rancidity indices of fried oil (total polar compounds (TPC), and triglyceride dimers-polymers (TGDP), among others) and e-nose based odor index. Fuzzy logic screened 6 MOS sensors (LY2/G, LY2/AA, LY2/GH, LY2/gCT1, T30/1, and P30/1) to deconvolute the rancid fried oils using hierarchical clustering on principal component space. A good relationship was noted between rancidity indices and odor index (R2>0.85). Based on maximum discard limits of rancidity indices (25% TPC and 10% TGDP), the frying disposal time of 15.2h (TPC) vs. 15.8h (e-nose) and 15.5h (TGDP) vs. 16.3h (e-nose) was determined. The demonstrated methodology holds a potential extension to different fried oils and products.

Ultrasound-assisted extraction of flavonoids and phenolic compounds from Ocimum tenuiflorum leaves

Ultrasound-assisted extraction (UAE) was optimized for extraction of flavonoids and phenolics from dried leaves of Ocimum tenuiflorum using response surface methodology with a central composite rotatable design and independent variables of ethanol concentration (30-70%), sonication time (5-15 min), and ultrasonic energy density (UED) (0.15-0.35 W/cm3). A significant (p<0.0001) quadratic model described experimental data with a non-significant lack of fit (p>0.05). Linear and quadratic effects of independent variables significantly (p<0.001) influenced flavonoid content (FC) and total phenolic content (TPC) yields. Optimized UAE conditions of ethanol concentration, sonication time, and UED were 55.34%, 11.71 min, and 0.26 W/cm3, respectively, resulting in predicted FC and TPC yields of 6.69 mg of quercetin equivalents QE/g and 9.41 mg of gallic acid equivalents GAE/g, respectively. HPLC analysis revealed different phenolic and flavonoid compounds. UAE extracts exhibited better in vitro antioxidant activities and thermo-oxidative stability values than conventional solvent extracts.

Chemometric approach to develop frying stable sunflower oil blends stabilized with oleoresin rosemary and ascorbyl palmitate.

The frying performance of sunflower oil blends (SOBs) stabilized with oleoresin rosemary (Rosmarinus officinalis L.) (ROSM) (200-1500mg/kg) and ascorbyl palmitate (AP) (100-300mg/kg) were tested for 18hopen pan-frying. Sunflower oil with TBHQ (SOTBHQ) (200mg/kg) and without additives (SOcontrol) served as positive and negative controls, respectively. The frying stability was monitored over time by estimating the levels of conjugated dienes, total polar compounds, polymeric compounds viz., triglyceride polymers, dimers, oxidized triglyceride monomers, diglycerides and free fatty acids, and induction period based on Rancimat. Chemometric tools were used to classify the oil samples based on frying stability. Thermo-oxidative changes were reduced significantly for blends stabilized with ROSM and AP (p<0.05). Principal component analysis (PCA) and hierarchical cluster analysis (HCA) distinguished SOBs from positive controls. A formulation consisting of 1309.62 and 129.29mg/kg of ROSM and AP, respectively, was optimized using a hybrid PCA-RSM approach.

Antioxidant Activity and Polyphenol Content of Brassica oleracea Varieties

ABSTRACT Reasons for beneficial medicinal benefits to humans from cabbage (Brassica oleracea L. var. capitata) needs clarification. The research examined beneficial phytochemicals in cabbage that activate and stabilize antioxidant and detoxification mechanisms in humans. Methanolic extracts of red cabbage (B. oleracea L. var. capitata f. rubra [MERC]), green cabbage (B. oleracea L. var. capitata [MEGC]), cauliflower (B. oleracea L. var. botrytis [MEC]), and broccoli (B. oleracea L. var. italica [MEB]) were analyzed for antioxidant activity (AA) using different in vitro assays and polyphenol content. The AA was tested by radical scavenging activity of extracts against 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical, ferric reducing power, and ferrous ion chelation assay. The antioxidant activity from all assays was in the order MERC > MEGC > MEB > MEC. Total phenolic and flavonoid contents were highest and lowest for MERC (2.26 mg gallic acid equivalent [GAE]·g−1 fresh weight [FW] and 1.43 mg rutin equivalent [RE]·g−1 FW) and MEC (0.83 mg GAE·g−1 FW and 0.42 mg RE·g−1 FW), respectively, as were antioxidant assays. High-performance liquid chromatography analyses of extracts indicated presence of phenolic acid and flavonoid compounds confirming in vitro antioxidant behavior. There may be a rational for use of B. oleracea, especially red and green cabbage, in phytomedicine as a food supplement against diseases that involve free radicals.

Kinetics of lipid oxidation in omega fatty acids rich blends of sunflower and sesame oils using Rancimat

Blended sunflower (SO) (50-80%) and sesame oils (SEO) (20-50%) were evaluated for thermo-oxidative stability (induction period, IP), oxidation kinetics (rate constant, k), synergy and shelf-life (25 °C) (IP25) using Rancimat (100, 110, 120, and 130 °C). The Arrhenius equation (ln k vs. 1/T) and activated complex theory (ln k/T vs. 1/T) were used to estimate activation energies, activation enthalpies and entropies, which varied from 92.05 to 99.17 kJ/mol, 88.83 to 95.94 kJ/mol, -35.58 to -4.81 J/mol K, respectively (R2 > 0.90, p < 0.05). Oil blend (OB) with 1:1 SO to SEO exhibited greatest synergy (115%), highest IP (100 °C) (13.2 vs. 6.1 h) and most extended IP25 (193 vs. 110 days) with a nutritionally stable composition of ω-fatty acids (ω9, 34.5 vs. 28.7%; ω6, 49 vs. 52%) compared with SO. Better retention of lignans (6205 vs. 3951 mg/kg) and tocopherols (332 vs. 189 mg/kg) were also noted in OB compared with SO alone.