The effect of processing and packaging on the shelf life of peeled-sliced potatoes | |
| Author | Lakhe, Rehna |
| Call Number | AIT Thesis no.PH-01-7 |
| Subject(s) | Potato chips--Preservation Potato products--Preservation Potato Products--Packaging Potato chips--Packaging |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Abstract | A comparative study was carried out for extending shelf life of peeled sliced potatoes of Atlantic variety, by various treatments: blanching at low and high temperatures, application of chemicals and their combined effect with vacuum packaging, nitrogen flushed packaging and ordinary-sealed low density poly ethylene (LDPE) packaging. All samples were stored at 4°C, and in addition, LDPE packaged samples were stored at 0°C and 10°C. Browning index, reducing sugar, pH, total soluble solids (TSS), total viable counts, sensory quality tests and visual inspections were analyzed as an index of shelf life. Shelf life varied widely depending on packaging, from the range of 7 days at 10°C and 25 days at 0°C in LDPE packaging. At 4°C, it was found to be 34 days in nitrogen flushed packaging, 29 days in vacuum packaging and 20 days in ordinary sealed packaging. Among the treatment conditions, blanching at 100°C for 1.5 minutes was found to be the best in terms of browning inhibition. A good linear correlation was found between time-temperature for blanching with total solids (R2 = 0.909) and browning index (R2 = 0.853), respectively. Treatment of the potato slice with a mildly heated (45°C) solution of ascorbic acid, citric acid and sodium acid pyrophosphate at 1 % concentration of each was also found to be effective in inhibiting the browning process. Combination of treatments with packaging in vacuum nitrogen flushed packaging was found to enhance the shelf life greatly. The blanched samples, in overall, showed best retention of color as compared to control and chemical-treated samples. Blanched and control samples of all packagings had more total bacterial count and a faster growth was observed as compared to chemicaltreated samples. However, the range of viable cells count was found to be 103 to 106 CFU/gm. The chips made of chemical treated samples was scored as the most crispiest in texture followed by the blanched samples (P<0.05) by the testing panel, which was further verified by analyzing mechanical properties (maximum load, deformation, work done and stiffness) of the chips. A moderate correlation (R2 = 0.306 to 0.79) was found between sensory score and mechanical test parameters. |
| Year | 2001 |
| 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 | Postharvest and Food Process Engineering (PH) |
| Chairperson(s) | Athapol Noomhorm; |
| Examination Committee(s) | Jindal, Vinod K. ;Rakshit, Sudip K. |
| Scholarship Donor(s) | NORAD; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2001 |