Thumbnail Image

Thesis

Browse

2017 - 201922020 - 20211
Reset filters
Subject: Microbiology × Author: Jaspreet Kaur × Start date: 2017 × Thesis Type: M.Sc ×
Reset filters

Search Results

Now showing 1 - 3 of 3
  • Thumbnail Image
    ThesisItemRestricted
    Value addition of Agaricus bisporus (Lange) Sing. through paste preparation
    (Punjab Agricultural University, Ludhiana, 2021) Jaspreet Kaur; Sharma, Shivani
    Agaricus bisporus (button mushroom), most widely cultivated edible mushroom, serves the potential to grow on agricultural wastes. Button mushroom being highly perishable in nature, deteriorates immediately after harvesting. Due to this reason, the fresh mushrooms needs to be processed for extending their availability throughout the year. This can be achieved by implementing adequate post harvesting technology and processing into value added products. Therefore, the present work has been dealt with preparation of mushroom paste for shelf life improvement and utilization of this paste as supplement in pasta and soups and as an ingredient in noodles and cookies. The strain U3 showed maximum yield potential (16.38 kg/q compost) by short method of compost as compared to long method. The different mushroom pastes (MP I, MP II, MP III) were prepared and stored at room and refrigerated temperature in glass containers, plastic containers and tetra-packs. All the mushroom pastes showed acceptable physical, chemical and microbial properties at refrigerated temperature in glass containers followed by tetra-packs and plastic containers. Among these three mushroom pastes, MP I showed higher appearance score in glass containers while MP II showed better color and taste score in tetra-packs at refrigerated temperature. The chemical properties (total soluble solids, total sugars and ascorbic acid) and microbiological count were acceptable for MP I in glass containers at refrigerated temperature. Protein content (7.68µg/ml) was maximum in glass containers for MP (control) followed by MP I up to 15 days. Pasta and cookies prepared from MP I was found to be most appropriate in terms of organoleptic properties. While for preparing soup and noodles, all the mushroom pastes were found to be equally good in terms of all parameters such as color, flavor, texture, taste and overall acceptability. Thus, the preparation of value added products not only extend the shelf life but also enhance the income by value addition and marketing.
  • Thumbnail Image
    ThesisItemRestricted
    Effect of freeze tolerant baker‟s yeast on dough rising
    (Punjab Agricultural University, Ludhiana, 2018) Jaspreet Kaur; Katyal, Priya
    Among the sophisticated, ready to use frozen products, frozen dough is gaining considerable attention. So, attempt was made to improve freeze tolerance of baker‟s yeast strain by trehalose loading and cold acclimatization and to design its product formulations. Loading with 1.0M trehalose after 7 days of incubation led to increased intracellular trehalose content from 0.3% to 4.71%. Comparative freeze tolerance studies of parent and treated baker‟s yeast revealed that 14 day cold acclimatized culture exhibits maximum cell viability (193cfu/ml) under refrigerated conditions while further incubation for 21 day (167cfu/ml) and 28 day (165cfu/ml) lowered the cell viability. The 28 day cold acclimatized culture showed higher total sugar content of 36.29% followed by 1.0M trehalose loaded culture (29.44%). Maximum trehalose content (4.71%) was shown by 1.0M trehalose loaded culture. Minimum invertase (29.79 nmol/min/ml) and maximum maltase activity (627.99 nmol/min/ml) was shown by 1.0M trehalose loaded culture and 21 day cold acclimatized culture, respectively. Biomass production of baker‟s yeast was carried out at conditions pre-optimized in our laboratory:- pH-6.0, aeration-120 rpm and temperature-30⁰C using unclarified molasses as carbon source and corn steep liquor (CSL) as nitrogen source. Best dough rising ability was shown by 14 day cold acclimatized culture. Product formulation as cream yeast and dried (lyophilized and tray dried) yeast was prepared, out of which cream yeast was used in bread making while nutritional profiling of dried yeast formulations showed the presence of crude protein (23.39-28.98%), crude fat (2.14-2.73%), zinc (7.26-10.13mg/100g), iron (27.54-28.09mg/100g), phosphorus (463.9-593.44mg/100g), calcium (2913.7-5308.38mg/100g), tryptophan (0.71-1.09g/100g protein), methionine (0.73-0.83g/100g protein) and cysteine (0.38-0.4g/100g protein). The present study revealed that cold acclimatization of baker‟s yeast can improve its freeze tolerance. Among the two yeast formulations, cream yeast has been found to be suitable for use in dough rising for bread, while dried yeasts can be exploited as nutritional yeast by further testing for required parameters.
  • Thumbnail Image
    ThesisItemOpen Access
    Post harvest processing of Pleurotus florida (Mont.) singer into mushroom soup powder
    (Punjab Agricultural University, Ludhiana, 2017) Jaspreet Kaur; Sodhi, H.S.
    Oyster mushroom is the third largest cultivated mushroom in the market. Pleurotus species are popular and widely cultivated in the world. Pleurotus spp. altogether make up 27% of globally produced cultivated mushrooms. Cultivation of Pleurotus florida is easy and low cost production technology. They can degrade and colonize large variety of lignocellulosic wastes. They can grow within temperature range of 20C to 30C. Pleurotus florida was grown on wheat straw, wheat+paddy straw (1:1) and paddy straw substrate. Maximum yield of (60.12 kg/q dry straw) was observed on wheat straw substrate. Similarly maximum fruit bodies (6870 per/q dry straw) were observed in the bags filled with wheat straw. The average weight of fruit bodies in all the cases ranged between (7.79-8.06gm/f.b‘s). The spawn run was completed between 21±3-25±2 days and pin heads appeared between 25±2-33±3 days with the first harvest made between 28±3-39±2 days. P. florida mushroom could be kept for 2-4 days at ambient temperature and could be stored for 12 days at refrigerator temperature in polyethylene, polypropylene and paper bags. It was observed that mushroom drying increased the shelf life of mushrooms upto three months. Among the three drying temperatures (45C, 55C and 65C), 45C was found best as it resulted in good colour, texture and rehydration ratio. The carbohydrate, protein, fat, fibre and ash of dried mushrooms was ranged between 41.59-42.85%, 27.40-29.54%, 4.21-4.32%, 23.01-23.38%, 8.81-9.03%. Being highly perishable in nature, the fresh Pleurotus mushrooms need to be processed to extend the offseason availability. Mushroom soup powder was one such option for improved shelf life of the mushrooms. Three set of mushroom soup powders; without flavour, lemon flavour, mint flavour were prepared and scored by ten judges on ten hedonic point scale for colour, texture, appearance, aroma, taste and overall acceptability upto six months of storage. Mushroom soup powder without flavour was the most acceptable giving an overall acceptability between 9.20-9.25 followed by mint flavour and lemon flavour soup powder. The moisture content ranged between 5.00- 5.11%. Protein, carbohydrate, fat, fibre and ash ranged between 17.3019.42%, 71.03-77.01%, 2.21-3.12%, 3.42-4.01%, 0.89-1.20%. There was no significant effect of storage on the nutrients of soup powder upto six months at room temperature.