Comparative analysis of nutritional qualities and evaluaiton of post-harvest techniques of jews ear mushroom (Auricularia auricula)
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Date
2023-04-19
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Department of Plant Pathology, College of Agriculture,Vellayani
Abstract
The present study entitled “Comparative analysis of nutritional qualities and evaluation of post-harvest techniques of Jew’s ear mushroom (Auricularia auricula)” was carried out in College of Agriculture, Vellayani during 2021-2022, with the objective of evaluation of the nutritional quality and analysis of various post-harvest
techniques, organoleptic properties and influence of supplementation and growth regulators on the yield enhancement of A. auricula. Survey was conducted in sixteen locations of 3 different Agro Ecological Units (AEU) of Southern Kerala viz. AEU 8, AEU 9 and AEU 12 during the North
East Monsoon season of 2021. Sporocarps of Auricularia were collected from tree stumps, from 6 locations. Most of the mushrooms collected were gregarious in nature
and all the mushrooms were lignicolous in habitat. Morphological studies showed that sporocarps were light brown to dark brown in colour and mostly ear shaped. Microscopic observations revealed that the size of basidia as well as mycelial width were higher in Nilamel isolate (AEU 9) whereas basidiospore size was highest in
mushrooms collected from Kulathuppuzha. In vitro culture of the collected isolates in potato dextrose agar media and potato dextrose broth showed fastest mycelial growth as well as highest mycelial weight in case of mushrooms collected from Nilamel region. Molecular characterization of the collected mushrooms using LSU primers confirmed all the
isolates to be A. auricula at species level showing a similarity of more than 98%. The best isolate ie, Nilamel isolate of AEU 9 when used for spawn production in paddy
grains took an average of 28 days for the complete spawn run with fluffy mycelial growth and a keeping quality of around 72 days. Major contaminants observed during
spawn production were Aspergillus sp. and Trichoderma sp. Evaluation of different supplements (10 % of rice bran, bengal gram powder, spent mushroom compost and poultry manure and 2% of urea and ammonium sulphate) for the production of A. auricula revealed that rice bran was the best
supplement over others which took comparatively lesser days for pinhead formation (43.00 days) as well as significantly higher yield (308.42 g). Among various growth regulators viz., Indole-3-Acetic Acid (IAA), Indole-3- Butyric Acid (IBA), Gibberellic Acid (GA), Naphthalene Acetic Acid (NAA) and Kinetin supplied at a concentration of 10 ppm to the beds amended with rice bran, GA was found to be the best which showed minimum days for the complete spawn run, and pin head formation (33.67 days and 37.33 days respectively) and significantly
higher yield (413.37 g). Major contaminants observed during the cultivation of A. auricula were bacteria, Trichoderma sp. and Coprinus sp. Incidence of pests like sciarids, Megaselia sp. and slugs were also observed during the cultivation. Analysis of nutritional quality of A. auricula in comparison with that of Pleurotus florida (both supplemented with 10 per cent rice bran and treated with 10 ppm GA) revealed that carbohydrate content (dry weight basis- 61.02 %), moisture content (fresh weight basis- 89.37 %) and minerals like calcium (1.61 %) and sodium
(0.94 %) of A. auricula were higher compared to that of P. florida. A significantly lower fat content (1.59 %) was also observed in A. auricula than P. florida. Evaluation of effect of supplementation on the nutrient composition of the mushroom showed that supplementation with rice bran (10 %) resulted in a significantly higher
level of carbohydrate (61.21 %) and ash content (5.33 %), Urea (2 %) supplementation led to higher level of crude protein content (14.23 %) and that of
spent mushroom compost (10 %) supplementation provided comparatively higher level of crude fiber (18.37 %) and fat (2.01 %). Minerals like calcium, sodium and
potassium were significantly higher in mushrooms produced by supplementing with 10 per cent poultry manure. Evaluation of post harvest preservation techniques of the mushroom revealed that freeze drying was the best method to preserve A. auricula for a longer duration of 120 days whereas steeping was found to be least effective with a shelf life of only 25days. Major contaminants observed during the preservation of the mushroom include, Aspergillus sp., Trichoderma sp., Penicillium sp. and a gram negative bacteria. Organoleptic properties of A. auricula (fresh and dried) was compared to that of P. florida, Calocybe indica, and Agaricus bisporus and it suggested that the overall acceptability of A. auricula was comparable with that of other mushrooms and dried Auricularia was preferred to fresh by most. The results of the study indicated that supplementation can enhance both yield
as well as nutritional quality of Jew’s ear mushroom. Rice bran can be used as the best amendment and GA as the best growth regulator for A. auricula cultivation. Freeze drying can be adopted as the best preservation method for Jew’s ear mushroom. High yield, good palatability, high nutritional quality and long shelf life make this
mushroom more acceptable.