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ThesisItem Open Access Evaluation and utilisation of edible lichen parmotrema tinctorum (Nyl.) hale for food preservation(Department of Post Harvest Technology, College of Horticulture, Vellanikkara, 2018) Anupama, T V; KAU; Sheela, K BInvestigation on “Evaluation and utilisation of edible lichen Parmotrema tinctorum (Nyl.) Hale for food preservation” was carried out in the Department of Post Harvest Technology, College of Horticulture ,Vellanikkara during 2014-2017. The main objectives of the study were to evaluate the biochemical constituents, proximate composition, antimicrobial activity, feasibility for food preservation and to study the toxicological effect of the lichen Parmotrema tinctorum. The lichen samples were collected from Chembra, Meppadi, Moolankavu and Ambalavayal areas in Wayanad district, and they were identified as Parmotrema tinctorum by colour spot tests. The samples read K-, C+, KC+ and Pd- for the lichen Parmotrema tinctorum. The habitat of lichen was found to be the shady places of the evergreen forests at 736m -2100m above MSL. Parmotrema tinctorum is found to be corticolous (growing on the surface of trees) in habit. Thallus of the lichen is foliose, loosely attached, lobes irregular, margins entire, upper surface grey, smooth, shining; lower surface black and marginal area brown. Proximate analysis of Parmotrema tinctorum revealed a high content of total protein (15.70 %), crude fibre (14.16%), ash (10.50%) and total phenols (322 mg/100g). Parmotrema tinctorum also contained total carbohydrate (20.03 g/100g), crude fat (1.28%), ascorbic acid (4.66 mg/100g) and total free amino acids (8.25 mg/g). High content of calcium, magnesium, potassium and iron were found in the mineral analysis of Parmotrema tinctorum. Methanol, ethyl acetate and acetone extracts of Parmotrema tinctorum were analysed for antioxidant activity by DPPH and ABTS assays, and the highest scavenging action was detected in the methanol extract against the DPPH free radicals (IC50-1.47 mg/ml) and the ABTS radicals (IC50-1.27 mg/ml). Preliminary phytochemical screening of Parmotrema tinctorum revealed maximum phytochemicals in methanol extract viz. carbohydrates, phenols, flavonoids, tannins, terpenoids, fixed oils and coumarins. The TLC profiling of lichen extracts (hexane, methanol and acetone) showed maximum compounds in acetone extract, and the spots indicated the presence of phenols and terpenoids. A range of volatile compounds were observed when the lichen extracts (methanol, hexane, acetone, chloroform and ethanol) were subjected to GC-MS analysis.Volatile compounds with antimicrobial properties identified were orcinol, methyl orsellinate, atraric acid, atranorin, methyl haematommate, glyceryl trilaurate, lauric acid vinyl ester and gamma-sitosterol. In vitro testing of antimicrobial activity of acetone, ethanol and chloroform extracts of Parmotrema tinctorum using disc and well diffusion methods revealed their inhibitory action against the selected food spoilage organisms. Ethanol extract (EE) of Parmotrema tinctorum produced maximum inhibition of Aspergillus niger, while chloroform extract (CE) produced maximum inhibition of Aspergillus oryzae. The growth of both yeast species, Saccharomyces cerevisiae and Zygosaccharomyces bailii, was found to be inhibited maximum by the ethanol extract followed by the chloroform extract of the lichen Parmotrema tinctorum. In both disc diffusion and well diffusion methods, the growth of Bacillus subtilis and Staphylococcus aureus were remarkably inhibited by the acetone extract (AE) followed by chloroform extract (CE) forming zones of inhibition at all the concentrations tested. Feasibility of utilizing Parmotrema tinctorum for food preservation was evaluated by adding in powder and in ethanol extract form in two processed products viz. lime pickle and tomato sauce. In lime pickle, bacterial count was least in treatments T8 and T7 (added with 0.3% and 0.2% ethanol extracts respectively). Product preserved with 250 ppm sodium benzoate (T2) revealed least fungal count (0.6x103 CFU/g), which was on par with that containing 0.3% ethanol extract (1.0x103 CFU/g). Lowest yeast count was observed in T8, followed by T2 (0.3 x103 CFU/g). The shelf life of lime pickle treated with T2 (product preserved with 250 ppm sodium benzoate) was estimated to be six months, while that of T8 (product treated with 0.3% ethanol extract) was found to be five months. Unpasteurised tomato sauce in which 0.1% ethanol extract was added had significantly lower bacterial count (5.2X106 CFU/g). The tomato sauce preserved with 750 ppm sodium benzoate recorded lowest fungal and yeast count. The products added with 0.05% and 0.1% ethanol extract of lichen also recorded lower fungal and yeast counts. Microbial analysis of products showed the relevance of ethanol extract as an alternative to sodium benzoate in preventing the microbial spoilage of foods. Sensory analysis revealed that lichen extract added products were acceptable for consumption. Acute oral toxicity study of the ethanol extract of Parmotrema tinctorum conducted in Wistar rats revealed the absence of clinical signs of toxicity and mortalities. There were no treatment related changes in body weight and gross pathological changes in the test animals. Single dosing of ethanol extract of Parmotrema tinctorum upto a dose of 2000 mg/kg body weight orally was found to be safe in Wistar rats.ThesisItem Open Access Aloe vera based edible film coating for shelf life extension in tomato (solanum iycopersicum)(Department of Post Harvest Technology, College of Agriculture, Vellayani, 2018) Thushara, T Chandran; KAU; Mini, CThe present investigation on “Aloe vera based edible film coating for shelf life extension in tomato (Solanum lycopersicum)” was carried out at the Department of Post Harvest Technology, College of Agriculture, Vellayani during the period of 2014-2017, with the objective to standardise an Aloe vera gel based edible film coating for tomato fruits to withstand storage and transportation losses and thereby formulate a viable and efficient post harvest management practice for extending shelf life of tomato. A preliminary trial was conducted for standardization of Aloe vera gel based edible film using four different gelling agents (INS 401, 402, 440 and 508), seven concentrations (1, 2, 5, 10, 15, 25 and 35%) and five durations (1, 2, 5,10 and 15 minutes) for extending shelf life of tomatoes. Based on the physiological loss in weight and shelf life obtained, 12 superior treatment combinations including INS 401 and 402 at 1 and 2% concentrations dipped for 1, 2 and 5 minutes were selected for further study of the experiment. Further experiments were carried out as four different steps using tomato variety Akshaya, harvested independently at two different maturity stages viz., mature green and firm ripe which were meant for distant and local market transportation respectively. Evaluation of the selected 12 aloe gel based edible films on quality parameters revealed the superiority of aloe gel based treatments over untreated fruits harvested in both the maturity stages. Shelf life of aloe gel based edible film coated mature green and firm ripe tomatoes were 36 and 24 days respectively. On the 36th day of storage all the aloe gel based treatments were equally effective in maintaining chemical and microbial quality parameters of the mature green tomato fruits, but fruits dipped in 2% aloe gel + INS 402 for two minutes recorded least PLW and percent leakage and hence had higher scores for sensory parameters. Firm ripe fruits dipped in aloe gel +INS 402 (1%) for one minute had superior physical and physiological parameters on 24th day of storage. The possibility of increasing the efficiency of aloe gel based formulation by incorporation of natural and cheap plant leaf extracts from papaya, guava and ocimum in 1:1 and 1:2 ratios for shelf life extension in tomato was assessed. Considering the economics and efficiency in maintaining better physiological quality parameters, 2% papaya leaf incorporated aloe gel (1:2) + INS 402 for two minutes was selected as the best plant leaf extract incorporated aloe gel (PLEAG) treatment for mature green fruits and 1% papaya leaf incorporated aloe gel (1:2) + INS 402 for one minute for firm ripe tomatoes. Quality evaluation of edible coatings revealed better efficiency of papaya leaf incorporated aloe gel (1:2) in reducing the activity of texture affecting enzymes viz., pectin methyl esterase and polygalactouronase and increasing total pectin content resulting in higher fruit firmness in both mature green and firm ripe tomatoes. Even though no antimicrobial activity against Erwinia and Rhizopus was noticed when tested under in vitro condition, the aloe based extracts had suppressed the post harvest infection by these pathogens in vivo. Efficiency of the selected papaya leaf incorporated aloe gel (1:2) in reducing post harvest loss during storage and transportation was compared with that of a commercial wax formulation independently for mature green and firm ripe tomato fruits after packaging in 5% ventilated corrugated fiber board (CFB) boxes with and without moulded tray. When packaged fruits were stored under optimum low temperature (12- 200C for mature green and 10-150C for firm ripe) and ambient temperature (28-300), low temperature storage was superior in maintaining the quality parameters for both the maturity stages of tomato. Packaging in 5% ventilated CFB boxes with moulded tray was effective in maintaining the physical and physiological parameters of mature green tomato during storage. Papaya leaf incorporated aloe gel (1:2) was equally effective as the commercial bee wax formulation in maintaining the physiological, chemical, and microbial parameters. Fruits coated with commercial bee wax had reduced lycopene content and a non- uniform fruit colour development and hence recorded poor sensory scores. Though both the packaging systems were equally effective in maintaining all the quality parameters during storage of firm ripe tomatoes, overall acceptability was higher for fruits kept in 5 % ventilated CFB box with molded trays. Papaya leaf incorporated aloe gel (1:2) was equally effective as the commercial wax formulation for the stored firm ripe tomatoes too. Studies to analyze the efficiency of aloe gel based coatings to withstand transportation losses revealed the superiority of 5% ventilated CFB box with moulded tray and effectiveness of papaya leaf extract incorporated aloe gel (1:2) in maintaining all the quality parameters in fruits of both maturity stages. Cost of production for coating the standardized papaya leaf incorporated aloe gel was Rs. 45.87/- for 100 Kg mature green tomatoes and Rs.23.65/- for 100 Kg firm ripe tomatoes. Based on the study, an efficient postharvest management practice for shelf life extension in tomato fruits of both maturity stages could be formulated. Mature green tomato fruits cv. Akshaya after washing and surface sanitization using 2ppm ozonized water for five minutes followed by coating with papaya leaf incorporated aloe gel (1:2) + INS 402, (2%) for two minutes, air drying and packaging in 5% ventilated CFB boxes with moulded tray had a storage life of 60 days under optimum low temperature (12-200C) or could be transported to distant markets without transportation hazards. Firm ripe tomato fruits cv. Akshaya could be stored for 36 days using the same protocol except coating with papaya leaf incorporated aloe gel (1:2) + INS 402, (1%) for one minute and storing at an optimum low temperature of 10-150C or could be transported to local markets without any hazards.