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Title of Thesis

Biometric and Biochemical Studies on Hot Pepper

Author (s)
Qumer Iqbal
Institute/University/Department Details
Institute of Horticultural Sciences, University of Agriculture Faisalabad, Pakistan
Session
2009
Subject
Horticulture
Number of Pages
184
Keywords (Extracted from title, table of contents and abstract of thesis)
Sky red, plastic mulches, immature green

Abstract

Studies were conducted to evaluate the impact of plastic mulches viz. black, clear andbare soil in the modification of plant growing environments on three hot pepper hybrids namely Sky Red, Maha and Wonder King in poly/plastic tunnels during the year 2005-06 and 2006-07. Hot pepper hybrids and plastic mulches had significant effect on plant growth and yield attributes. By using clear plastic mulch intensive weed proliferation was problematic issue; however under black plastic mulch almost complete weed suppression was achieved which results in increased fruit yield than hot peppers grown under clear plastic mulch and bare soil (control).
The pattern of antioxidant accumulation was envisaged in hot peppers harvested at different stages; immature green, mature green, color break, red ripe and dried fruit. Capsaicinoids had significant distribution in mature green stage while progressive accretion of carotenoids and ascorbic acid was observed at dried and red ripe stage of all hybrids, respectively. However, the pattern of total phenolic contents biosynthesis was found significant at immature green stage in Sky Red where as in Maha at color break stage and in case of Wonder King at red ripe stage.
Aflatoxin contamination in hot pepper hybrids was investigated under various temperatures (20, 25 and 30C) and packaging regimes (polyethylene and jute bags) during five months storage period. Aflatoxin detection under these conditions had lower levels than the existing regulatory limits ascribed by European Commission (EC No. 1881/2006) that is 10μg kg-1 for total aflatoxins. Aflatoxin contamination and microbial load was increased significantly with the increase in temperature and storage duration which was heavily infested when samples packed in jute bags and stored at 25 and 30C respectively. Storage duration and temperature regimes had inverse relation on antioxidant quality of hot pepper ecotypes as well.
Further attempts were made to decontaminate aflatoxin contaminated samples of hot pepper hybrids (from previous study) subjected to gamma radiation (2, 4 and 6 kGy) and its effect on antioxidant stability was again assessed after three month storage. Higher the irradiation dose, lower the concentration of carotenoids and ascorbic acid ascertained in hot pepper ecotypes; however, capsaicinoids and polyphenols rendered greater stability at higher irradiation dose during storage. Irradiated samples of hot peppers had 7% xii reduction in aflatoxin contamination as compared to non-irradiated (control). Total fungal population had inverse relation with increasing radiation dose and complete inhibition was observed when irradiated at 6 kGy and no further fungal proliferation was seen during three months storage at ambient conditions.

 

         
Full Thesis


1435 KB

S. No. Chapter Title of the Chapters Page Size (KB)
1 1 Introduction 1
34 KB
       
       
 
2 2 Review of Literature 6


245 KB

  2.1 Use of plastic mulches in vegetable production 7
  2.2 Hot pepper as a source of antioxidants 14
  2.3 Aflatoxin contamination as a serious concern 22
  2.4 Aflatoxins, microbial load and irradiation 31
         
3 3 Materials and Methods 36  


102 KB

  3.1 Effect of plastic mulches on growth and yield of hot peppers 36
  3.2 Quantification of antioxidant constituents in hot peppers harvested at different stages 41
  3.3 Evaluation of hot peppers for aflatoxin contamination, microbial load and antioxidant quality during storage 44
  3.4 Effect of gamma-radiation on microbial load and antioxidant quality of aflatoxin contaminated samples during storage 47
  3.5 Statistical analysis 48
         
4 4 Results and Discussion 49
757 KB
  4.1 Experiment I. Effect of plastic mulches on growth and yield of hot peppers 49
  4.2 Experiment II. Quantification of antioxidant constituents in hot peppers harvested at different stages 77
  4.3 Experiment III. Evaluation of hot peppers for aflatoxin contamination, microbial load and antioxidant quality during storage 96
  4.4 Experiment IV. Effect of gamma-radiation on microbial load and antioxidant quality of aflatoxin contaminated samples during storage 121
         
5 5 Summary 140
44 KB
       
       
         
6   References 146
123 KB