M.G.F. Chowdhury
Scientific Officer
Postharvest Technology Division, BARI, Gazipur
M.N. Islam
Professor
Food Technology & Rural Industries, BAU, Mymensingh
A.F.M. Tariqul Islam
Scientific Officer
RARS, BARI, Iswardi, Pabna
M.S. Hossain
Assistant Engineer
BADC, Rajshahi, Bangladesh
Mixed juice, Wood apple, Papaya, Shelf-life
Laboratory of the Department of Food Technology and Rural Industries, BAU, Mymensingh and Postharvest Technology Division, BARI, Joydebpur, Gazipur
Postharvest and Agro-processing
The experiment was conducted jointly in the laboratory of the Department of Food Technology and Rural Industries, Bangladesh Agricultural University, Mymensingh and Postharvest Technology Division, Bangladesh Agricultural Research Institute, Joydebpur, Gazipur during 2004 to 2005. Materials: The fresh, mature and ripe wood apple and papaya were procured from the local market. The pulp from a single variety of wood apple and papaya were used in this experiment. Citric acid, gum (acacia), car boxy methylcellulose (CMC), potassium meta bisulphite (KMS), sugar and other materials were collected from the local market. The glass bottle was used in the bottling of juice. Extraction of wood apple pulp: Fresh, fully ripe and sound wood apples were used for extraction of pulp. Wood apples were washed thoroughly and then peeled with gloved hand. The pulp was collected by squeezing out fresh of the wood apples. After blending the wood apple pulp was screened through a mosquito net cloth and pasteurized at a temperature of 75°C for two minutes. The pasteurized pulp was stored in a deep freeze at a temperature of −20°C for future use. Extraction of papaya pulp: Fresh papayas were washed thoroughly and peeled. The edible portions were separated from non-edible portion by knives. The edible portion was cut into slices. Then the crushed pieces were transferred to the juicer for separating the juice and pulp. The juice was collected after sieving the pulp and it was stored at -200C temperature for further use. Analysis of raw wood apple and papaya pulp: These pulp were analyzed for its moisture content, total soluble solid (TSS), acidity (as citric acid), pH, vitamin-C content (ascorbic acid), reducing sugar, non-reducing sugar and total sugar were determined according to Ranganna (1994). Formulations of mixed juice: Eight different treatments coded as T1, T2, T3, T4 T5, T6,T7 and T8, were selected for the study. Two types of thickening agents gum (acacia) and carboxy methyl cellulose (CMC) were used in the formulations. The treatments were as follows: T1=10% mixed pulp+9.38%sugar+0.25%citric acid+1.5%gum(acacia)+0.06%KMS, T2=11% mixed pulp+10.19%sugar+0.25%citric acid+1.5 %gum(acacia)+0.06%KMS, T3=12% mixed pulp+11.01%sugar+0.25%citric acid+1.5%gum(acacia)+0.06%KMS, T4=13% mixed pulp+11.82%sugar+0.25%citric acid+1.5%gum(acacia)+0.06%KMS, T5=10% mixed pulp+10.38%sugar+0.25%citric acid+0.5%CMC+0.06%KMS, T6=11% mixed pulp+11.19%sugar+0.25%citric acid+0.5%CMC+0.06%KMS, T7=12% mixed pulp+12.01%sugar+0.25%citric acid+0.5%CMC +0.06%KMS, T8=13% mixed pulp+12.38%sugar+0.25%citric acid+0.5%CMC+0.06%KMS. Preparation of mixed juice: The wood apple and papaya pulp (1:1) was taken for using different treatment on the basis of TSS (14%) and acidity (0.39%). Calculated amount of wood apple pulp, papaya pulp, sugar, citric acid, KMS, gum (acacia), CMC and water were weighed out. Sugar and citric acid were mixed with water and then the mixer was heated to prepare syrup. Then the syrup was filtered through a fine mosquito net cloth. Measured amount of gum (acacia) or CMC were mixed with hot syrup and then cooled. The measured quantity of mixed pulp was added to the syrup and blended for 2-3 minutes. After blending, the required KMS was added and stirred thoroughly for uniform mixing. This prepared juice was then centrifuged by Disc Bowl Centrifuger (model: anmfield FT15) to separate heavy particles. Blended beverage was again filtered through a fine net cloth and the 0.06% KMS were added and stirred thoroughly for uniform mixing. After centrifugation the prepared mixed juice was blended again and heated at 750C for 2 minutes. Then the mixed juice was bottled into a sterilized bottle and stored at room temperature (28-320 C) for future use. Microbiological studies: The prepared juice was studied for microbial load. The total microbial load was calculated by standard plate count method. Sensory Evaluation: Sensory evaluations of all the formulated mixed wood apple and papaya juices were done by taste testing panel. The taste testing panels were consisting of 10 test panelists. They were asked to evaluate colour, flavour, sweetness, sourness, stickiness, thickness and overall acceptability by a scoring rate on a 9 point hedonic scale. In this scale ‘like extremely’ is given the highest score of 9 and ‘dislike extremely’ is given the lowest score of 1. Others are given intermediate scores. The difference preferences as indicated scores were evaluated by statistical methods. The analysis of variance method (ANOVA) was used for this evaluation. The difference was quantified by Duncan's Multiple Range Test (DMRT). Analysis of formulated mixed juice: Mixed juice was formulated using 10-13% mixed pulp and adding thickening agents gum (acacia) and CMC and other additives as shown in treatment. To recommend optimum condition, mixed juice was analyzed for selected compositions for storage periods up to 6 months at room temperature. Selected mixed juices were subjected to organoleptic taste test. Storage studies: Processed mixed juices were stored at room temperature (28-320C). The different parameters for assessing deterioration and spoilage of mixed juices were observed at one month of interval.
Journal of Soil and Nature. 2 (3):50-60, 2008
Journal