13. Evaluation and preparation of guava jam stored at ambient temperature
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Abstract
The research work was on the effect of pectin on the textural property and storage stability of guava fruit jam stored at ambient temperature. The research was conducted at ARI, Tarnab, Pakistan in the lab of Food Technology section. The aim of the study was to study the effect of storage stability of guava fruit jam when stored at ambient temperature. The treatment was design with 1:1 ratio of guava pulp and sugar with different level of pectin content. All the treatments were studied physico-chemically and sensor ally for 90 days with 15 days’ interval. The increased was observed in TSS of Guava fruits jam from, % acidity and reducing sugars. It was found from statistical analysis that the value of non-reducing sugar of the jam reduced considerably (p<0.05) during 90 days of storage interval. While decreased was observed in pH (3.61 to 3.44), non-reducing sugars (42.95 to 23.45%), Ascorbic acid (92.8 to 71.52 mg/100g), color score (7.1 to 4.31), taste score (7.60 to 4.71), texture score (7.21 to 4.41) and acceptability score (7.51 to 4.65). The mean sensory scores for texture of the jam decreased significantly (p<0.05) on both treatments and storage intervals. The pH value decrease significantly, the high acidity of fruit jam might be due to the hydrolysis of starch to acid. Storage intervals and treatments significantly (p< 0.05) affect the color of guava jam during storage interval. Further studies need to be done to study the effect of storage on jam preservation and quality effects.
Keywords: Ambient Temperature; Guava frui; Jam; Pectin