Development of preservation by processing technologies of BAU kul

This study reports on processing of jam, jelly and chutney from BAU kul and assessing the products shelf life and food value. This study was conducted in the laboratory of the Department of Food Technology and Rural Industries, Bangladesh Agricultural University, Mymensingh. The fruits were collected from the local market and the pulp was extracted and analyzed for proximate composition. The proximate analysis of BAU kul pulp showed 86.12% moisture, 19.00% TSS, 06.04% reducing sugar, 15.16 % non-reducing sugar, 21.20% total sugar, 01.35% ash, 04.50P H , 00.44% acidity and 65mg/100g vitamin C. A total three types of products each with 3 different formulations were prepared and packed in appropriate packaging for storage studies. Products were stored at room temperatures and change their physical and chemical condition during storage was observed at an interval of 30 days for a period of four months. A taste panel consisting 10 panelists studied the acceptability of the samples. The consumer’s preferences were measured by statistical analysis of the scores obtained from the responses of the taste panel. Among the samples jam of (TSS – 65.50%, pectin – 0.5%, P H – 3.10), jelly of (TSS – 66.50%, pectin 0.5% and P H – 3.15) and chutney of (TSS – 65.5%, P H – 3.20) were awarded the highest scores by the panelists.


Introduction
The bar or jujube (Zizyphus mauritiana Lamk, 2n = 48) belonging to the family Rhamnaceae is the most hardy fruit tree cultivated all over Bangladesh and India (Singh, 1979) and also one of the most ancient common fruits of India (Yamdagni, 1985).It is commonly known as 'boroi' or 'kul' in Bangladesh and is one of the important fruits of Bangladesh.Some of the xerophytic characters and its ability to withstand drought makes it as "king of fruit's of arids".There is about 1214.57hectares of land under ber trees with a total production of 224000 m ton and yield (184.43 t/ha) in Bangladesh (BBS, 2006).The cultivated varieties in Bangladesh are BAU Kul, Apple Kul, BARI Kul-2, Narikeli, Dhaka-90, etc.
The BAU Kul resemble small apple in flavour and appearance and the pulp is mealy and sweet.It has a thin, edible skin surrounding whitish flesh of sweet, agreeable flavor.The fully mature fruit is entirely red.Shortly after becoming fully red, the fruit begins to soften and wrinkle.At this stage the flesh is crisp and sweet, reminiscent of an apple.Under dry conditions BAU Kul lose moisture, shrivel and become spongy inside.Ripe fruit can be preserved by sun drying and may be powdered for out of season purposes.
There appears to be considerable opportunities for expending production of BAU kul to meet increasing domestic demand.Especially in char land it is produced large quantities and mostly wasted due to the lack of proper processing and preservation.Only a small portion of BAU Kul is processed and preserved by housewives and small processors traditional like sun drying and pickle processing.Bangladesh cannot use high technology, sophisticated machineries and equipment, skilled manpower and large capital investment for modern food processing industries as in developed countries.Therefore it is important to develop and use low level appropriate technology for processing and preservation of jam, jelly and chutney made from BAU Kul.If it is processed and commercially exploited, the benefits would include improvement in average firm incomes and improved nutrition among consumers as it contains appreciable quantities of vitamin C and carotene.Principal constraints to the growth in supply of fruits in the country include post-harvest losses (an average of 26%) due to inadequate packaging, transportation and storage and lack of familiarity with good post-harvest practices or processing.
Therefore, the scope of utilizing BAU Kul remains bright in Bangladesh.Development of varieties of products like jam, jelly and chutney utilizing local produces is critically important for expanding the country's developing food industries.With the above points into consideration the present study has been designed to achieve the following objectives: i) Assessing composition of BAU kul determined, ii) Formulation and processing of Jam, Jelly and chutney finalized, iii) Shelf-life of the processed products evaluated, iv) Sensory attribute of the processed products assessed.

Materials and Methods
The fresh green BAU kul collected from the local market.The other materials used in the study were foodgrade chemicals and preservatives, sugar, spices, packaging materials etc.

Extraction of BAU kul pulp and juice
The fully mature fresh healthy BAU kul were washed thoroughly with potable water.After that, the flesh by knife for discarding seed.Water was added equal to the weight of the flesh and blended by blender for preparation of pulp.The pulp was sieved through stainless steel sieve for extraction of juice.

Chemical analysis of BAU kul pulp
Vacuum oven drying method described by Endel Karmas (1980) was used for determining moisture where the temperature was maintained at 70°C and pressure 50-100 mg of Hg.The acidity was determined by titration using standard sodium hydroxide solution and expressed as anhydrous citric acid and P H was measured by a P H meter.The ascorbic acid content in the products was estimated by titrimetric method summarized by Rangana & Bajaj (1979) using 2-6, dichlorophenol dye.AOAC (2004) method was used to determine the ash content of the products.

Formulation of BAU kul different products
The product prepared from BAU kul with different formulations were coded as; Jam: A 1 A 2 A 3 , Jelly: B 1 B 2 B 3, Chutney: C 1 C 2 C 3 The formulations of different products was shown in the Processing of BAU kul Jam/Jelly: Selected jujubes and BAU kul were weighed and washed thoroughly in cold water.Cut the washed fruits with a stainless steel knife into small pieces.Extracted pulp (Fig. 1) from fruit was adjusted the pH by addition of citric acid or sodium hydroxide.Strained the mass through a course cloth to separate the extract, took one more extract and mix them.Kept the mixed extract in deep a container and after settling, carefully decant the extract.The pectin was mixed in 3 proportions 0.5, 1.0 and 1.5% with sugar thoroughly.The martial was cooked the mixed juice till its TSS reached 65% (tested by Refractometer).The cooking temperature maintained at 104-105°C.Added Citric Acid and KMS and cooled.The finished products poured into clear dry sterilized glass jars.Selected fresh BAU kul were weighed and washed them thoroughly in cold water.Cut the washed fruits with a stainless steel knife into small pieces.The pieces were mixed with tamarind, sugar, salt, spices, Ginger, Garlic, Cumin Powder, Pachforon, Joyetri & Joyfal, Postodana, Chilli powder.The mustard oil was heated to boiling and the pulp mixture was added into it.After heating few minutes vinegar was added into it.The heating was continued until the mixture became brown in colour and TSS reached 60%.After that citric acid and KMS were added at three different proportions in the finished products.
Finally the soft brown mass was filled hot in glass jars and immediately capped.

Distribution
The required ingredients for different types of BAU kul chutney are shown in Table 3. Selection of fresh mature BAU kul after that weight and wash them thoroughly in cold water.Cut the washed fruits with a stainless steel knife into small pieces.The pieces are mixed with sugar, salt spices like kismis, ginger, garlic, cumin powder, pachforon, joyetri & joyfal, posto dana, chilli powder.The mustard oil was heated to boiling and the pulp mixture was added into it.After heating few minutes vinegar is added into it.The heating was continued until the mixture became brown in colour and T.S.S. reached 65%.After that citric acid was added three different proportions in the finished products.Finally the soft brown mass was filled hot in glass jars and capped immediately.

Chemical analysis
The wheat and sweet potato flours and the prepared instant noodles were analyzed for moisture, protein, fat, ash, crude fiber, starch content, peroxide value, and free fatty acid value by AOAC ( 2004) method.The total carbohydrates were calculated by approximation i.e. by subtracting the measured protein, moisture, fat and ash from 100 (Srivastava & Sanjeev, 2002).Sensory evaluation of all the formulated BAU kul Jam, Jelly and Chutney was done by taste testing panel.The taste testing panel was made up with of 10 test panelists.They were asked to evaluate, color, flavor, sweetness, sourness, stickiness, thickness and overall acceptability by a scoring rate on a 9 point hedonic scale.The scale was arranged such that: 9 = Like extremely; 8= Like very much; 7= Like moderately; 6= Like slightly; 5= Neither like nor dislike; 4= Dislike slightly; 3 = Dislike moderately; 2 = Dislike very much; 1 = Dislike extremely.The preference deference was evaluated by statistical analysis of the data for variance and consequently Duncan's Multiple Range Test (DMRT).

Storage studies
Processed BAU kul Jam, Jelly and Chutney were stored at ambient temperature (27°C to 34°C) for a period of 4 months and quality parameters were assessed.During storage the changes in TSS, acidity, P H , color, flavor, texture/turbidity and vitamin C and visual fungal growth were observed.The analyses of the parameters were done according to standard analytical methods summarized by AOAC (2004) and Rangana (1994).

Composition of BAU kul pulp
The composition of fresh BAU kul pulps such as moisture, ash, protein, fat, P H TSS, reducing sugar, nonreducing sugar, total sugar, acidity and vitamin-C content have shown in Table 4.  Islam et al.(2004).Islam et al.(2004)reported that TSS, Acidity, P H was 18.5,0.40and 4.12 respectively

Composition of BAU kul products
Vitamin C content in BAU kul pulp was found to be good compared to other citrus fruits.It was further reduced in jellies, jams and chutney prepared from BAU kul pulp because most of the ascorbic acid present in the pulp was destroyed during long heating at high temperature.This destruction was probably attributed due to neutralization of acid during inversion of sugars in juice and also resulted an increasing in reducing sugar content in jams, jellies and chutney.The average results are presented in Table 5. 3.4 no gel formation occurs at the usual soluble solid range.The optimum concentration of soluble solid is about 67.5%.It is, however possible to make jellies with high content of pectin and acid, containing less than 60% sugar.Too high quality of pectin necessary to form jelly depends largely on the quality of pectin.Only one percent should be sufficient to produce a firm jelly.

Storage Studies of BAU kul Products
Processed BAU kul jam, jelly and chutney, were stored at ambient temperature (27°C to 34°C) for a period of 4 months and quality parameters were assessed.During storage the changes in TSS, acidity, P H , color, flavor, texture/turbidity and vitamin-C and visual fungal growth were observed.The analyses of the parameters were done according to standard analytical methods summarized by AOAC (2004) and Rangana (1994).Results are presented in Table 6, 7 and 8.A panel of 10 judges tested the color flavor, texture and overall acceptability of the BAU kul products like jam, jelly and chutney manufactured with variable ingredients and the mean scores are presented in Table 9, Table 10 and Table 11.

BAU Kul Jam
Ten judges evaluated the color, flavor, texture and overall acceptability of three samples.Analysis of variance was carried out for color preferences and the results revealed that there were significant (p<0.05)differences in color acceptability since the calculated F-value (19.18) was greater than the tabulated F-value (3.55).The results showed in Table 9 that A 3 and A 1 were equally acceptable at 0.05% level of statistical significance.Samples A 2 and A 3 were equally preferable in respect flavor and the score for these two was 7.50 out of 9.In case of texture and overall acceptability preference among the samples, the results showed in that A 3 was the most preferred sample than other samples.Where, Error degrees of freedom =18, No. of judges = 10 -The means with same superscripts within a column are not significantly different at p<0.05 -A1 was processed by 1.5% pectin, A2 was processed by 1.0% pectin and A3 was processed by 0.50% pectin.

BAU kul Jelly
Analysis of variance was carried out for color preferences and the results revealed that there were no significant (p>0.05)differences in color acceptability.The results showed in Table 10 that B 1 was the most preferred one followed by B 2 and B 3 in respect to color preferences.In case of flavor and overall acceptability preference among the samples and the results showed that B 3 was the most preferred one.
In case of texture preference among the samples, analysis of variance (ANOVA) showed that there was no significant difference for texture preferences between B 1 and B 3 .Where, Error degrees of freedom =18, No. of judges = 10 -B1, was processed by 1.5% pectin, B2 was processed by 1.0% pectin and B3 was processed by 0.50% pectin.

BAU kul chutney
As shown in Table 11 that was no significant difference for color, flavor and overall acceptability preference among the samples a two-way analysis of variance (ANOVA) was carried out and the results showed that C 1 was the most preferred one.In case of texture preference among the samples, analysis of variance (ANOVA) showed that C 3 was the most preferred sample than other samples.Where, Error degrees of freedom =18, No. of judges = 10 -C1 was processed by 3gm citric acid, C2 was processed by 4gm citric acid and C3 was processed by 5gm citric acid.

Conclusion
This work was initiated to characterize the product prepared from different percentage of pectin for jam and jelly of BAU Kul.Three samples of jam and jelly were processed incorporating of 1.5%, 1.0% and 0.5% pectin and analyzed the physical, chemical and organoleptic characteristics.The amount of sugar and preservative gradually reduced to establish the effect of the suitability of chutney preparation.The Physical chemical analysis shows that reduce the pectin percentage reduce the stability of storage.Simultaneously reduce the sugar and not used preservative loss the storage stability.Moreover BAU kul is a good source of nutrients as well as its product jam, jelly and chutney.In addition, the BAU kul products has a great commercial value to reduce the poverty by developed food industry.

Fig. 1 .
Fig. 1.Process Flow-chart of Jam/Jelly manufacture Titre volume of the sample (ml) T b = Titre volume of the blank (ml) Meq. of N 2 = 0.014 Therefore, % Protein = % Nitrogen  6= Titre, N = Normality of NaOH, V 1 = Volume made up, E = Equivalent weight of acid, V 2 = Volume of sample taken for estimation, W = Weight of sample mg of vitamin C per 100g sample = = Titre , D = Dye factor, V 1 = Volume made up, V 2 = Aliquot of extract taken for estimation, = Fehling's Factor, D = Dilution,T = Titre, W = Weight of sample % Non-reducing sugar = % Invert sugar -% Reducing sugar % Total sugar = % Reducing sugar + % Non-reducing sugar Sensory Evaluation

Table 4 .
Chemical Composition of raw BAU kul

Table 5
Proximate Composition of BAU kul products

Table 6 .
Storage Studies of BAU kul Jam

Table 9 .
Duncan's Multiple Range Test (DMRT) for Color, Flavor, Texture and Overall Acceptability of BAU kul Jam

Table 10 .
Duncan's Multiple Range Test (DMRT) for Color, Flavor, Texture and Overall Acceptability of BAU kul Jelly

Table 11 .
Duncan's Multiple Range Test (DMRT) for Color, Flavor, Texture and Overall Acceptability of BAU kul Chutney