Study of quality deterioration of shrimp by chemical, microbial and electronic nose analysis | |
| Author | Salvi, Deepti Arvind |
| Call Number | AIT Thesis no.FB-05-01 |
| Subject(s) | Seafood industry Shrimp industry |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. FB-05-01 |
| Abstract | Seafoods contains high amount of non protein nitrogen and are highly susceptible to spoilage and deterioration caused by autolysis and growth of postmortem microbial population. With conventional sensory, microbial and chemical analysis, simple and rapid tests based on electronic nose are needed to assess seafood quality. Also interrelationship between these methods needs to be studied. Chemical and microbial analysis and a portable electronic nose (Cyranose 320rM) were used to study freshness of shrimp. In the first part of study, changes in quality of shrimp during storage were monitored using chemical, microbial and electronic nose analysis. The shrimps were stored under different conditions such as in ice and saltwater, ice and freshwater and at different temperatures (0, 5, 12, 20°C and at room temperature of about 28°C). Shrimps were analyzed at certain interval using total volatile basic nitrogen (TVBN), total plate count (TPC) and also by electronic nose. During storage, gradual increase was observed in TVBN initially and a sudden increase after TVBN value reaches to a level of about 25-35 mg N/100g. Interestingly the TVBN never reached spoilage limit of 35 mg N/100g for the shrimps kept in ice. This was perhaps due to leaching of volatile bases. TPC was also found increasing with time and temperature. TVBN and TPC appeared to be related and their relationships with time and temperature were also determined. For storage study electronic nose was able to classify samples with different levels of freshness in a particular storage condition using canonical discriminant analysis (CDA) and principle component analysis (PCA). Even small change in TVBN and TPC was taken in account by electronic nose. In second part of study, electronic nose patterns were recorded in random fashion for shrimps with different freshness levels including the samples in storage study. The freshness was determined by conventional chemical method (TVBN value). The patterns from electronic nose were used to predict TVBN value by multiple linear regression (MLR), partial least square regression (PLS-R) and artificial neural networks (ANN). The models developed by MLR, PLS-R and ANN were not found to be promising in view of lower values of coefficients of determination in 0.3-0.65 range. An attempt was made to classify the electronic nose patterns based on arbitrary limits of TVBN values and Euclidean distance. Considerable overlapping was detected among the classes. After removal of iced treatments, a three layer back propagation neural network was able to classify patterns with overall success rating of about 93.54 % based on two classes corresponding to different TVBV ranges (above and below 35 mg N/100g) |
| Year | 2005 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. FB-05-01 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Food Engineering and Bioprocess Technology (FB) |
| Chairperson(s) | Jindal, V. K.; |
| Examination Committee(s) | Athapol Noomhorm;Rakshit, S. K.; |
| Scholarship Donor(s) | Royal Netherlands Government ; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2005 |