Title of Invention

"AN IMPROVED PROCESS FOR STORAGE OF FRESH MUSHROOMS"

Abstract

A process for the storage of fresh mushrooms consisting storing the fresh mushrooms in polypropylene bags of 150 - 200 gauge with perforations (pinhole to 1 cm dia.) 1 - 8 numbers per bag of size 16x25 cm , characterized in that cooling at a temperature ranging from 2 - 5°C and an RH ranging from 60 - 80%, providing aeration @ a average 5 - 10% to the storage container, testing the microbiological quality at a regular interval of every 2 days, obtaining a product with characteristic mushroom flavor, texture, microbiologically safe and shelf life of 12 to 16 days.

Full Text

The present invention relates to an improved process for storage of fresh mushrooms. The present invention particularly relates to the extension of storage life of fresh button (Agaricus) and oyster (Pleurotus) mushrooms, the two largest varieties of mushrooms produced in the world. / Mushrooms in fresh form are highly perishable due to their high water content and fast rate of metabolism, involving active respiration. They tend to lose water content, turn brown and develop off-flavour. Not more than 24 h, they can be held in acceptable condition at room temperature. Mushrooms are consumed mainly for their characteristic biting texture and pleasant flavour. Any means of processing, to extend the storage life, alters one or both of these properties. In that way, there is an increasing awareness for consumption of the fresh produce, particularly in the international trade. India as an agricultural country, which can afford to produce significant quantities of mushrooms, if required to earn considerable foreign exchange by way of export and also to boost internal consumption, the need to extend storage life of fresh mushrooms is very vital. Reference may be made to the work of Maaker-J-de (1971) Champignoncultuur 15(6); 221-223 wherein, an extension of storage life by 41 h is recorded, when the mushrooms were stored in punnets covered with cellophane film. In another reference by Burton (1988) Mushroom Journal No. 183 ; 510 wherein, a storage life of four days is observed for the mushrooms, when packed in punnets covered with a microporous film. Yet in another reference Saxena and Rai (1988) Mushroom Journal for the Tropics 8(1) ; 15-22 wherein, a storage life of 1, 2 and 4 days at 15, 10 and 5°C respectively are recorded for the fresh mushrooms. Yet in one more reference, Technical Bulletin No. 2, Post-harvest Technology of Mushrooms, (1990) NCMRT, Solan, page 7 wherein, an extension of storage life of the fresh mushrooms is achieved upto 4 days at 5°C in 100 guage polyethylene bags. In all the above references cited, storage life of fresh mushrooms never exceeded 4 days, even at refrigerated temperature of 5°C. Such a short storage life limits the mushroom trade over distance, particularly from sites of production to sites of consumption, in the International trade, since only few countries have easy access to economic production of particular variety of mushrooms on commercial scales. In the present invention, the shelf life of fresh mushroom was extended by 12-16 days based on the variety, by altering physical factors like storage temperature, packaging material — aeration, permeability to 02 and C02, package density and storage relatively humidity (RH) without the use of any chemical or preservative. The main object of the present invention is to provide an improved process for storage of fresh mushrooms. Another object of the present invention is to achieve extended storage life of fresh mushrooms. Yet another object of the present invention is to avoid the use of any chemical during mushroom preservation, eventually to achieve "Organic Status" quality of the fresh produce stored. Accordingly, the present invention provides a process for the storage of fresh mushrooms, which comprises: (a) storing the fresh mushrooms in polypropylene bags of 150 - 200 gauge with perforations (pinhole to 1 cm dia.) 1-8 numbers per bag of size 16x25 cm ; (b) characterized in that cooling at a temperature ranging from 2 - 5°C and an RH ranging from 60 - 80%; ( c) providing aeration @ a average 5 - 10% to the storage container; (d) testing the microbiological quality at a regular interval of every 2 days; (e) obtaining a product with characteristic mushroom flavor, texture, microbiologically safe and shelf life of 12 to 16 days. In an embodiment of the present invention, two major varieties of the mushroom viz., Agaricus and Pleurotus were studied. In another embodiment, storage of fresh mushroom was undertaken under the micro-environment created by a combination of storage conditions. In yet another embodiment of the invention the film used is polypropylene with a preferred guage of 150-200, to condition CO2 to ~5%. In further embodiment of the invention safe microbiological count is CFU/g in case of Agaricus and The process entails the use of fresh mushrooms (Agaricus or Pleurotus) immediately after harvest and cleaning from the adhering substrate particles, after grading, packed in 150-200 gram quantities in 150-200 guage polypropylene bags (16x25 cm). The bags were earlier made with 1 cm perforations (8 No.) or pin hole according to mushroom variety required to be stored. The bags were sealed and arranged in foldable plastic crates (60x38x22 cm with 5-10% aeration) in two layers. So packed mushrooms were stored at temperature from 0-8°C and RH 60-80%. At periodic intervals, the stored mushrooms were subjected to microbiological and sensorial analysis. Storage life of 12 and 16 days could be achieved for Agaricus and Pleurotus mushrooms respectively. The following examples are given by way of illustration of the present invention and its use for storage of fresh mushrooms, and therefore should not be construed to limit the scope of the present invention. EXAMPLE -1 Fresh button (Agaricus bisporus) mushrooms immediately after harvest were cleaned and packed in 200 g quantities in each of 200 guage polypropylene bags (16x25 cm) with 8 perforations. The packs after arrangement in foldable plastic crates with 8% aeration, were stored at 2±1°C with a storage relative humidity conditioned to 80%. The mushroom quality was acceptable in terms of whiteness, texture and flavour, besides the safe microbiological quality upto 16 days. Under the conditions of storage wherein the concentration of C02 was conditioned to be at about 5%, total bacterial count did not exceed the permissible limit of 7 log™ CFU/g. EXAMPLE - 2 Fresh white oyster mushroom (Pleurotus florida) immediately after harvest, cleaning and trimming, were packed in 150 g quantities in each of 150 guage polypropylene bags (16x25 cm) with single pin hole. The mushroom packs after arrangement in foldable plastic crates with 5% aeration were stored at 5±1°C with a storage RH conditioned to 60%. Till the end of 12 days, the stored mushrooms were acceptable when evaluated for sensorial and microbiological qualities. EXAMPLE - 3 Fresh grey variety mushroom (Pleurotus sajor-caju) after harvest were cleaned and packed, holding the mushrooms under the conditions defined as in example 2. The mushrooms stored in acceptable condition for 12 days with safe microbiological quality. Mushrooms in fresh form due to high water activity (90% moisture content), richness in phenolics, phenoloxidases, lack of protective covering, are very delicate commodities to be retained, in acceptable condition for more than 24 h. Their high respiratory rate and tendency to lose water content faster lead to fast perishability. Use of chemical/preservative likely to influence the colour, texture and mild flavor of the mushrooms. Accordingly, the present invention was targeted to lower the physical activity of the fresh mushrooms by retarding the process of senescence through a combination of physical factors in the immediate environment of the stored fresh mushrooms such as packaging material, its permeability, aeration (for O2/C02 concentrations), package density, storage temperature and finally the storage RH. Quantification of these composite factors evolved serve to retain the moisture, color, texture and flavor. Further, assessing the microbiological quality of stored mushrooms also assumed equal importance, to define the safety for consumption. In the entire microbiological work, sterilization is achieved by autoclaving different growth and plating media, glasswares and other solutions for 20 min at 121°C. Microbiological profile of the fresh mushrooms Agaricus and Pleurotus were studied both at initial (soon after harvest) and during storage : Sample of mushroom in 11 g quantity was added to 99 ml of sterile 0.85% saline to get an initial 10~1 dilution. From this initial sample dilution, subsequent serial dilutions were prepared in 9 ml amounts of sterile 0.85% saline. Aliquots of appropriate sample dilutions in 1ml were pour plated with conventional nutrient medium such as Plate count agar (PCA), Me Conkey agar (MCA) and Potato dextrose agar (PDA). Poured plates of PCA, MCA and PDA were incubated at 37°C for 48h. Characteristic colonies of the specific bacterial species appearing in the incubated plates were counted and expressed as colony forming units per gram (CFU/g). Likewise, yeasts and moulds were also counted in the incubated PDA plates. The isolated bacterial isolates were characterized based on Gram's reaction, cell morphology, spore forming nature and motility, and biochemical tests. Likewise, characterization of the fungal flora was done conventionally, based on morphology and spore characteristics. The predominant food borne pathogenic bacterial species viz., Eschehchia coll, Staphylococcus aureus, and Bacillus cereus, were absent in both the types of mushroom samples, indicating the microbial safety. However, Bacillus staerothermophilus, and Pseudomonas aeroginosa were the major nonpathogenic bacteria identified (on the mushroom samples), which are the constituents of a natural habitat ; the CPU were within the permissible limit of 7 logic CFU/g. The novelty of the invention is as follows : Loss of moisture is not recorded here, unlike any other reference and despite the long storage life achieved, the stored mushrooms proved microbiologically safe, essentially due to conditioning of CO2 ~ 5%. However, in no reference a storage life as long as 12 or 16 days is achieved. In every reference, there is a loss of moisture of the mushroom to various degrees. Methods enunciated on the Controlled Atmosphere Storage of fresh mushrooms can not be practical, because of the high costs and requirement for the sophisticated equipment. The present invention encompasses to overcome these adverse features and more importantly serves to enhance the storage life of fresh mushrooms, two folds compared to the works reported till now in the world. The storage life is defined based on the data of microbiological safety and consumers' acceptability. The main advantages of the present invention are : 1. Extension of storage life of fresh mushrooms. 2. No chemical is used in the process. 3. Simple and adoptable process. 4. The process does not involve the use of sophisticated equipments/instruments. We Claim: 1. A process for the storage of fresh mushrooms, which comprises: (a) storing the fresh mushrooms in polypropylene bags of 150 - 200 gauge with perforations (pinhole to 1 cm dia.) 1-8 numbers per bag of size 16x25 cm ; (b) characterized in that cooling at a temperature ranging from 2 - 5°C and an RH ranging from 60 - 80%; ( c) providing aeration @ a average 5 - 10% to the storage container; (d) testing the microbiological quality at a regular interval of every 2 days; (e) obtaining a product with characteristic mushroom flavor, texture, microbiologically safe and shelf life of 12 to 16 days. 2. A process as claimed in claim 1 , wherein the fresh mushrooms are selected from a variety of Agaricus and Pleurotus. 3. A process as claimed in claims 1-2 wherein the safe microbiological count is 4. A process for storage of fresh mushrooms substantially as herein described with reference to the examples accompanying this specification.

Documents:

194-DEL-2003-Abstract-(10-07-2008).pdf

194-del-2003-abstract.pdf

194-DEL-2003-Claims-(10-07-2008).pdf

194-del-2003-claims.pdf

194-DEL-2003-Correspondence-Others-(10-07-2008).pdf

194-del-2003-correspondence-others.pdf

194-del-2003-correspondence-po.pdf

194-del-2003-description (complete)-10-07-2008.pdf

194-del-2003-description (complete).pdf

194-DEL-2003-Form-1-(10-07-2008).pdf

194-del-2003-form-1.pdf

194-del-2003-form-18.pdf

194-del-2003-form-2.pdf

194-del-2003-form-3.pdf