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A lutein-rich extract from African marigold (Tagetes erecta L.) flowers (packaged-irradiated) obtained by the green technology of supercritical carbon dioxide extraction at 450 bar (4.5 × 107 Pa), 80 °C after 105 min of extraction time had lutein content of 215.53 ± 3.75 mg/100 g dry basis (d.b.) and DPPH radical scavenging activity of 0.83 ± 0.03 mg/mL (IC50 value). This antioxidant-rich extract was microencapsulated by spray drying to improve shelf-stability of lutein. The encapsulation parameters were optimized using a Taguchi L9 orthogonal array design to obtain highest microencapsulation efficiency (ME%) under the experimental conditions. The optimized conditions of spray drying obtained were: spray concentration (%w/w) of 30, wall material composition of maltodextrin:gum Arabic :: 60:40, core (lutein):wall material :: 1:30, sample feed flow rate of 0.90 mL/min (1.5 × 10− 8 m3/s), inlet air temperature of 170 °C, spray gas flow rate of 742 L/h (2.06 × 10− 4 m3/s) and atomization pressure of − 60 mbar (− 6000 Pa). At these conditions ME(%) was found to be the highest (78.32%) w.r.t. lutein content (1.28 ± 0.05 mg/g powder). The encapsulate possessing highest ME% exhibited concomitant highest antioxidant activity (IC50 value of 2.33 ± 0.39 mg/mL and FRAP value of 6.16 ± 1.30 mM FeSO4 equivalent/g d.b.) vis-a-vis those obtained at other encapsulation conditions. Besides, half-life of the best encapsulate (Ebest) was 6.90 times higher than the native extract under ambient storage conditions (23 ± 2 °C, 80% R.H., in the dark). Along with Ebest, lutein-rich native extract and pure lutein were characterized by thermogravimetric/differential thermal analysis, X-ray diffraction analyses, field emission scanning electron microscopy and energy dispersive X-ray spectroscopy analyses. Ebest was then employed in designing a novel lutein-rich ready-to-serve beverage and its sensory, physicochemical and phytochemical properties were evaluated.

Extraction of eugenol from dried tulsi leaves powder (Ocimum sanctum Linn.) of ‘West Bengal origin’ (Eastern India), Ram tulsi variety, was carried out using supercritical carbon dioxide (SC-CO2) extraction. The optimized parameters for highest yield of eugenol [2.96 mg (g dry tulsi leaves)−1] were 20 g of tulsi leaves powder (dp = 0.42 mm) extracted at 50 °C, 200 bar and 90 min extraction time at a constant flow rate of 2.5 L min−1 of gaseous CO2. Statistical analyses revealed that only extraction pressure showed significantly effect on the yield of eugenol. The extraction kinetics of eugenol from tulsi matrix followed first order kinetics (Higuchi model). Characterization of the packed bed of tulsi leaves was also carried out during steady and unsteady states of extraction and empirical correlations were developed among dimensionless Reynolds, Sherwood and Schmidt numbers. The correlation coefficients were found to be low owing to leaf mucilage which impeded extraction of eugenol from tulsi leaves.

Optimization of supercritical carbon dioxide extraction parameters for ‘piperine’ extraction from Malabar black pepper ( Piper nigrum L.) has been conducted by a three-level full factorial design. The optimized conditions obtained were: 20 g pepper, mean particle diameter 0.42 mm, 300 bar, 60°C, 45 min extraction time and 2 L/min flow rate of gaseous CO 2 . A correlated Chrastil equation has been generated to predict solubility of piperine in SC-CO 2 under different extraction conditions. The extraction curve followed plug flow model. Extraction kinetics followed Higuchi model. The packed bed was characterized using an empirical correlation ( r =0.96) among Re, Sc and Sh numbers.

Black pepper (Piper nigrum L.), the King of Spices is the most popular spice globally and its active ingredient, piperine, is reportedly known for its therapeutic potency. In this work, enzyme-assisted supercritical carbon dioxide (SC-CO2) extraction of black pepper oleoresin was investigated using α-amylase (from Bacillus licheniformis) for enhanced yield of piperine-rich extract possessing good combination of phytochemical properties. Optimization of the extraction parameters (without enzyme), mainly temperature and pressure, was conducted in both batch and continuous modes and the optimized conditions that provided the maximum yield of piperine was in the batch mode, with a sample size of 20 g of black pepper powder (particle diameter 0.42 ± 0.02 mm) at 60 °C and 300 bar at 2 L/min of CO2 flow. Studies on activity of α-amylase were conducted under these optimized conditions in both batch and continuous modes, with varying amounts of lyophilized enzyme (2 mg, 5 mg and 10 mg) and time of exposure of the enzyme to SC-CO2 (2.25 h and 4.25 h). The specific activity of the enzyme increased by 2.13 times when treated in the continuous mode than in the batch mode (1.25 times increase). The structural changes of the treated enzymes were studied by (1)H NMR analyses. In case of α-amylase assisted extractions of black pepper, both batch and continuous modes significantly increased the yields and phytochemical properties of piperine-rich extracts; with higher increase in batch mode than in continuous.

Development of a methodology for rapid assessment of shelf-life of fried potato wedges were carried out using electronic noses (e-noses) with metal oxide gas sensors. Fuzzy logic analysis was applied for the first time for screening the sensors and it was found that four sensors were more specific for detecting volatile organic compounds from fried potato wedges. Data obtained from these screened sensors concluded that fried potato wedges had shelf-life of 3 days when stored in inert atmosphere of nitrogen in Ziploc pouches at 23 ± 2 °C. Mahalanobis distance method was adopted for quantifying the extent of spoilage and was correlated to peroxide values and free fatty acid content obtained by biochemical assays. Since, this methodology accurately and rapidly predicted the shelf-life of fried potato wedges; it could be also applied for fast and reliable estimation of shelf-life of various fried food products.

Extraction of antioxidant-rich fractions from lyophilized algal biomass of Phormidium valderianum was carried out by green technology of supercritical carbon dioxide (SC-CO 2 ) extraction. Optimization of extraction parameters (temperature and pressure) was carried out to obtain an extract that has the best combination of phytochemical properties (phenolic content, carotenoid content, reducing power and antioxidant activity) with minimum toxin content (Anatoxin-a). The algal extract obtained by SC-CO 2 from 10 g biomass at 50 °C, 500 bar after 1.5 h extracting time at a flow rate of 2 l min − 1 of gaseous CO 2 had maximum phytochemical properties with ~ 93% reduction of Anatoxin-a content. This investigation provides an alternative method for obtaining natural antioxidants from algae for food and pharmaceutical applications.

Microencapsulation of eugenol-rich clove extract obtained from clove buds by supercritical carbon dioxide (SC-CO 2 ) extraction was carried out in maltodextrin and gum arabic matrices using spray dryer. Microencapsulated powder with maximum encapsulation efficiency of 65% was obtained with 1:4.8:2.4 of clove extract: maltodextrin: gum arabic. The morphology of the encapsulated powder was determined from SEM photographs; while its phytochemical properties such as total phenolic content, total eugenol content and antioxidant activity were determined by biochemical assays. Food application in soybean oil was designed using the encapsulated clove powder as a source of natural antioxidant. Comparative evaluation of the antioxidant efficacy of encapsulated clove extract, un-encapsulated clove extract and commercial antioxidant BHT, individually administered in soybean oil, established encapsulated clove extract as a promising natural antioxidant in the same.

Ocimum sanctum Linn., commonly known as Tulsi in India, is pharmacologically important owing to its active constituents, chiefly eugenol. In this work, supercritical carbon dioxide (SC-CO 2 ) extraction has been performed with Krishna tulsi to maximize the yield of eugenol in the extracts and comparatively evaluated against conventional extractions. Phytochemical analyses of chlorophyll-lean and chlorophyll-rich SC-CO 2 extracts showed promising results. SC-CO 2 extract with maximum eugenol content (4.631 mg g −1 dry tulsi powder) was obtained at 70 °C, 400 bar and 1.5 h extracting time. However under these extraction conditions, appreciable amount of cuticular waxes and chlorophyll co-eluted. Eugenol-enriched (4.141 mg g −1 dry tulsi powder) chlorophyll-lean extract was obtained at 50 °C, 100 bar after 1.5 h extracting time. Comparative study of phytochemical properties of extracts obtained by several extraction techniques, established that the SC-CO 2 extract has the best combination of eugenol and phenolic content along with reducing power, anti-inflammatory, antimicrobial and antioxidant activities. The chlorophyll-rich and chlorophyll-lean extracts of SC-CO 2 extracts have comparable phytochemical properties. SC-CO 2 extraction has been successfully employed for extraction of eugenol from Krishna tulsi with appreciable nutraceutical potency. We envisage that both chlorophyll-lean and chlorophyll-rich extracts of the same would have promising applications in food and pharmaceuticals.

Extractions of anthocyanins from peels of eggplant ( Solanum melongena L.) using GRAS solvents and supercritical carbon dioxide (SC-CO 2 ) were investigated. Conditions of solvent extraction that provided maximum yield of anthocyanin were water–ethanol (1:1, v/v) in 10% citric acid at 60 °C. The highest yield of the same by SC-CO 2 was a sample size of 10 g of peels at 60 °C, 10 MPa, 1.5 h extracting time and 2 L min −1 of CO 2 . Delphinidin-3-glucoside and delphinidin-3-rutinoside were tentatively identified as the major anthocyanins in the extracts. The total phenolics, proanthocyanidin content and antioxidant activity of the solvent-extracted color were significantly higher than those in the SC-CO 2 extracted color. Stability studies concluded that the former was more stable at high temperature regimes. Trace metal content in the SC-CO 2 extracted color was significantly lower. Usage of the SC-CO 2 extracted color in non-thermal food applications is recommended owing to its higher stability and low metal contamination.

Supercritical fluid extraction (SFE) using carbon dioxide is a popular technique for oil extraction due to its high extraction efficiency, short extracting time, lower refining requirement and absence of chemical residues or contamination in the extracted oils. In this work, an attempt has been made to extract oil from a local variety of cottonseed using this technique. The effects of the extraction parameters of pressure, temperature and time of extraction of oil were optimized by using statistical techniques such as central composite rotate design (CCRD) and response surface methodology (RSM), with a view to maximize the oil yield with minimum gossypol extraction. From this study, it could be concluded that the yield of cottonseed oil can be improved at pressure higher than 550 bar, in the temperature zone of 70–80 °C and extracting time of 2–3 h.

A comparative evaluation of the extraction of 2-acetyl pyrroline (2-AP) from Pandanus amaryllifolius Roxb. using either solvent extraction (3:1 chloroform:methanol), Likens–Nickerson apparatus or supercritical fluid extraction (SFE) with carbon dioxide extraction was carried out. SFE at 450 bar pressure for 3 h at 60 °C, at a constant flow rate of 0.1 l min−1 of CO2, could extract 2-AP from P. amaryllifolius Roxb. in yields greater than those obtained by solvent extraction or Likens–Nickerson extraction. This extract could find novel applications in food flavouring.

Pullulan, an extracellular polysaccharide is obtained by fermentation using a fungus, Aureobasidium pullulan . To obtain the pure biopolymer from the fermentation broth, cell harvesting, removal of the melanin pigments co-produced during fermentation and precipitation of the polymer are essential. The present work reports on some of these aspects. Centrifugation of the fermentation broth (at optimized fermentation conditions) at 800 rpm for 30 min gave a cell pellet that was discarded and a greenish black supernatant containing the melanin pigments. The supernatant was subjected to demelanization by adsorption on activated charcoal, or by use of solvent/solvent blends, or by solvent/salt combinations, all after denaturation of the pullulanases at 80 °C/1 h. Among all these treatments, a combination of ethanol/ethyl methyl ketone in 60:40 ratios was found to be most effective. Melanin separated out in the solvent blend, while the pure pullulan that precipitated out was comparable in colour and texture to that of the commercial sample.

Volatile long chain hydrocarbons, such as 1-tetradecene, 1-hexadecene and 8-heptadecene, could serve as marker compounds in cashew nuts irradiated at 0.25–1.00 kGy. Monitoring these markers over a storage period of 6 months under ambient conditions showed them to be persistent. The concentrations of the markers increased linearly with radiation dose at all storage periods of the study. However, their concentration decreased marginally with storage at all the dose levels.

Cashew nuts, an important export item from India, contribute to about 7% of the national exchequer. Insect infestation of the cashew nut, leading to economic losses is a frequently encountered problem. The present work aims to combat this problem by using low dose γ-irradiation and evaluating the effect of such treatment on the physico-chemical properties of cashew nuts. Cashew nuts, irradiated at 0.25, 0.50, 0.75 and 1.00 kGy and stored under ambient conditions were analyzed periodically every 2 months for 6 months with respect to the changes in 10-kernel weights, colour characteristics and proximate composition. Visual inspection showed no insect infestation for six months, even at 0.25 kGy, while the control sample was totally infested. This was evident from the 10-kernel weights, which decreased gradually with time of storage. While an increase in yellowness of the cashew nuts was observed as a function of storage time and irradiation dose, no substantial changes in proximate composition between the samples or with storage time were observed. This study underlines the use of 0.25 kGy of irradiation for preservation of cashew nuts.