Organoleptic and Biochemical Analysis of Traditional and Customized Product of Shidhils

A detailed survey was conducted to collect information on the present status of traditional preparation procedure of Shidhil at the Northern region of Bangladesh. A total of 10 samples of traditionally prepared Shidhil was collected from Rangpur, Kurigram and Nilphamari districts and brought to the Department of Fisheries Technology in zipper polythene packets. Proximate composition of the traditionally prepared Shidhil showed that, percent moisture content in Rangpur samples was higher than other samples whereas the percent protein found higher in kurigram samples. Customized product of improved Shidhils were prepared in the same laboratory with kachki ( Corica soborna ), mola ( Amblypharyngodon mola ), punti ( Puntius ticto ) and mixture of these three species of fishes. The survey on traditional preparation procedure of Shidhil revealed that the traditional preparation procedure of Shidhil is quite similar among the districts though there were some differences in shape and weight. Variations were observed in the price of Shidhils per piece and it ranged from 10 to 40 taka/piece. No wholesaler could be found in the marketing channel of Shidhil and it is prepared mostly for home consumption. The biochemical study of the improved Shidhils showed that the percent mean value of moisture, protein lipid and ash of dried fishes obtained at the initial stage changed while Shidhil was prepared using these dry fishes. In the case of kachki fish percent moisture content increased from were 16.12 to 23.84. The percent mean value of protein of dried punti fish were 51.48 which decreased to 41.07% after preparing Shidhil . On the other hand, the percent lipid value was 15.08 for dried mola which increased to 24.25 in mola Shidhil . In the case of mixture of three species of these fishes the percent mean value of ash was 12.73 which decreased 10.38 after preparing Shidhil .


Introduction
Fermentation is a process which offers a wealth of possibilities and plays an important role in improvement of nutritional and functional properties of food.The WHO food safety unit has given high priority for the research in food fermentation, as it will improve the food safety by controlling the growth and activity of pathogens in foods.
Moreover, fermented food products are a good source of peptides and amino acids (Rajapakse et al., 2005, Sathivel et al., 2003).The calcium, phosphorus, magnesium and iron contents of Chepa Shutki were reported to be higher than those of similar kinds of Japanese processed fish and was regarded as a high quality protein food (Khanum, 1999).
Indigenous fish products, such as Shidhil is a salt-free, solid, semi-fermented one, prepared from small sized fish along with Kachu Data/Taro or other plants which is a specialized fish product of the northern region of Bangladesh (Gaibandha, Kurigram, Lalmonirhat, Rangpur, Nilphamari, Dinajpur, Thakurgaon).It has several local names such as Shidal, Hidal, Hentak etc. which varies from district to district.Beside this, another type of fish product called Sidal (sounds similar) or Cheapa shutki is prepared in other parts of Bangladesh (in many parts of greater Mymensingh) which totally differs from Shidhil in terms of processing and cooking.
Shidhil is prepared by the application of traditional method of drying followed by fermentation.A characteristic taste and flavor develops in the final product which is a delicacy.The process of Shidhil preparation does not cost much and it does not demand high technical knowledge.But Shidhil preparation procedure is usually carried out under an unhygienic condition and it is confined to some particular groups of people.Further, its marketing condition is also poor.Literature available on the various aspects of preparation of this product is scanty (Muzaddadi and Basu, 2003).
In Bangladesh, the nutritional deficiency has become more acute because of tremendous rate of population growth without any significant increase in animal protein production.In this regard, Nowsad (2007) reported, raw material quality is not often maintained during Shidhal or other fermented products such as-Nga-pi preparation.Till now, research on Shidhil preparation, its marketing channel are scare.Therefore, it is very important to investigate the present status of the product, it's preparation process, marketing channel and nutritional quality of this product.At the same time, it is also necessary to build up awareness about the practice of basic hygiene during manufacturing of the product and safety of the finishes one.A detailed study on traditionally produced Shidhil can provide valuable information in the use of the product on a wider scale.Formulation of new techniques to increase the shelf life would help in the commercialization of these products.
The present study was carried out to assess the present status and nutrition quality of the fermented product, Shidhil collected from Northern region of Bangladesh and improved Shidhil was prepared at laboratory maintain hygienic condition.Quality assessment of the laboratory prepared Shidhil was also done under various storage conditions.

Study area
For this study the survey was carried out on the present status of traditional preparation procedures of Shidhil practiced at Northern districts of Bangladesh, specially Rangpur, Kurigram and Nilphamari districts.

Survey on traditional Shidhil
The survey was carried out on a total of 10 retailers, 8 producers and 6 consumers of each district to collect relevant information by interviewing them individually using prescribed questionnaire.The informations were collected using a survey form where the questions were arranged under eight different sections likegeneral Information: (of producer / retailer / consumer), information of raw fish collector / producer / wholesaler / retailer, information of Shidhil seller, information about capital involved and cost-benefit, information about socio-economic condition of Shidhil traders, information about production, information about marketing and information obout sanitation and hygiene.At the time of interview each question was explained to the interviewee clearly and asked systematically.During interview tape-recorder and video camera were used whenever it was necessary for keeping the record.

Observation of traditional Shidhil preparation procedure and collection of traditionally prepared Shidhil sample
To observe the traditional production procedure of Shidhil at Northern region of Bangladesh (Rangpur, Kurigram and Nilphamari area) several producer's houses were visited.The traditional preparation procedure of Shidhil is presented in Plate-2.During the survey traditionally prepared Shidhils were collected for laboratory analysis.From Rangpur district 4 types of traditional Shidhils, 3 types from Kurigram district and 3 types from Nilphamari district were collected (Plate 3).A total of 10 types of samples were packed in zipper polythene packets and stored at room temperature (28 to 32°C) in food grade plastic container to bring them to the Fish Processing and Quality Control Laboratory of Department of Fisheries Technology, Bangladesh Agricultural University.
Preparation procedure of customized products of Shidhil (improved Shidhil).

Collection of fish and taro samples
To prepare improved Shidhil in the laboratory, three species of fishes-kachki (Corica soborna), mola (Amblypharyngodon mola) and punti (Puntius ticto) and Taro (Colocasiae sculenta) were collected in fresh condition from the local market of Mymensingh city (Plate 4).

Processing of giant taro
Mixing of dried fish and grinded taro by traditional mortar Preparation procedure of improved Shidhil The dried fish samples of Kachki (Corica soborna), Mola (Amblypharyngodon mola) and Punti (Puntius ticto) were grinded to prepare fish powder of each species and kept in separate plates until mixing with taro (Plate-6).

Preparation of fish sample
The gut content of collected fish samples were removed and washed properly using potable water.Fishes were then dried directly under sunlight for 5 days.Bamboo basket (locally called kula) was used to dry the fishes.Sun drying reduced the moisture content of fish samples.After completion of drying, the dried fish samples were packed in zipper polythene packets until further use (Plate-5).On the other hand, taro were peeled off, cut into small pieces and steamed for few minutes.The steamed taro pieces were poured on a clean-soft net to remove water.After removal of water the steamed taro was grinded to prepare taro paste.The powder of dried fishes were then mixed with taro paste and this mixture was kept in folded giant taro leaf for overnight to allow fermentation.Next day a little amount of turmeric powder and mustard oil (Table-1) were mixed with the fermented sample and a definite shape was given (patty shape).This patty shaped improved Shidhil were then dried under sunlight for 7 days (Plate 4).After draying these Improved Shidhil samples were stored in zipper polythene packets until analysis at different temperatures.

Quality assessment of Shidhil
Quality assessment of both traditionally prepared Shidhil and improved Shidhil was done in the laboratoriy of Department of Fisheries Technology, Bangladesh Agricultural University.

Sensory assessment of the Shidhil samples
A panel of nine-members (students, teachers and staffs of the Department of Fisheries Technology, Bangladesh Agricultural University) was selected for the sensory assessments of the products (method described by Nowsad et al., 2000).The Shidhils were evaluated for preference of color, flavor, odor, texture, taste and overall acceptability on the basis of defect points as describe in Table -2 and 3.

Biochemical analysis
Proximate composition (moisture, crude protein, lipid and ash) of Shidhils was carried out according to the methods given in AOAC ( 2000) with certain modifications.Triplicate samples were taken to carry out the experiment.

Statistical Analysis
Data from different biochemical measurements was subjected to statistical analysis.The statistical analysis package SPSS 11.5 (SPSS Inc, Chicago, IL, USA) was used to calculate mean values.

Survey on traditional Shidhil Marketing chain of Shidhil
Marketing is the connecting link between the producers and consumers.The study on the marketing system of traditionally prepared Shidhil (Flow chart) showed that there is no specific marketing channel; it varies depending on the place and season of the year.Producers collect raw materials of Shidhil from shukti arotdar or shutki retailer.In most cases, the shutki retailers produce Shidhil with the help of women of their own house.After making Shidhil, the shutki retailers takes it to his own shop and sell Shidhil directly to the consumers.From the study it was also observed that, no license is required for Shidhil business (Table 4).Shidhil is prepared almost round the year but the mostly prepared during the winter season due to having enough sunlight.The survey also showed that, almost in all villages of North Bengal and some houses in urban area, Shidhil are made for their own consumption not for sell.Some times on the basis of consumers demand the producers of urban area sell their Shidhil.

Cost and benefit analysis
A simple cost and benefit analysis was done for Shidhil preparation and sell (Table 5).The cost is more or less same round the year except the raw material cost varies depending on the season and availability.Study showed that, 400-450 pieces Shidhil are made from 10 kg small dry fish/shutki.The price of Shidhill varies from place to place.In Rangpur sadar, the price of Shidhil is 30 to 40 Taka per piece whereas in Kurigram, the price is 10 to 15 Taka per piece and in Nilphamari, the price is 25 to 30 taka per piece Shidhil.The price of 10 kg small dry fish/shutki is about 2500 taka in local dry fish arot.According to the Shidhil retailers, the consumer for Shidhil in local markets are very few, sometimes even a single piece of Shidhil is not sold in a day.Retailers also informed that, sometimes some consumers buy Shidhil to send  abroad to their relatives who are very much fond of Shidhil as traditional product of Northern districts of Bangladesh.The Shidhil retailers added, though Shidhil is a traditional food of Northern districts of country but the popularity of this product is increasing day by day.If the nutritional quality can be maintained properly the market of Shidhil will expand throughout the country.
During survey, information on price, shape, weight of Shidhil and spices used in Shidhil production in the study area were also collected.These information are presented in Table 6.Among the three districts the price/ piece of Shidhil was highest at Rangpur and was lowest at Kurigram.The shape of Shidhil was little different at Kurigram (diamond shape) but weight of the Shidhil/piece was highest (27 to 30 g/piece).Almost similar kinds of spices were used in Shidhil preparation except Rangpur district.

Organoleptic assessment of traditionaland improved Shidhils
The results of organoleptic quality study of traditional and improved Shidhils are presented in Table -7 and  Table 8.The Shidhils of bright brown color is considered most acceptable to the consumers.In case of odor, strong dried fishy odor is considered best and it is rejected when it smells rancid off odor.The hard texture of Shidhil is preferred by the consumers and considered excellent.
The defect point of traditional Shidhil collected from Rangpur district named as R1.R2 and R3 were found acceptable (Table 7) but the sample named as R4 was of excellent quality.Traditional Shidhils collected from Kurigram and named as K1, K2 and K3 and the Shidhils collected from Nilphamari (N1, N2 andN3) were also of excellent in quality.Analysis of proximate composition i.e. percent moisture, protein, lipid and ash contents of taro, three species of raw fishes, dried fishes, Shidhils prepared from these dry fishes was done and the obtained result is presented in Table -10.
Results of the proximate composition analysis of the fresh fish, dry fish and Shidhils (prepared with improved techniques) showed that-the percent moisture content increased in all samples after preparing Shidhils than the moisture content in the dried fishes (i.e., percent moisture content in dried kachki was 16.12 whereas the value was 23.84 in kachki Shidhil).On the other hand, the percent protein content decreased after preparing Shidhil than the protein content originally was in dry fishes (i.e., percent protein content in dried dried mola was 55.42 whereas the value was 44.25 in mola Shidhil).In the case of percent lipid content in the Shidhil samples turned almost double than in the dry fish samples (i.e., percent lipid content in dried punti was 13.05; whereas the value was 28.90 in punti Shidhil).Rahman et al. (2016) reported a range of protein and lipid content of 'Shidhil' produced from punti 31.3 to 51.32% and 5.81 to 6.71%, respectively.and for 'Shidhil' produced from silver jew fish with taro the lipid and protein content ranged from 30.54 to 49.4% and 5.03 to 6.45% , respectively.These values are quite nearer to the obtained values in the present experiment.The moisture content increased in the Shidhil samples than in the dry fishes in this study might be due to the addition of taro during the product preparation, as because taro contains more than 75% moisture content.On the other hand, the increment in the percent lipid content in the Shidhils might be contributed by the addition of mustard oil during product preparation procedure.

Conclusions
Through the survey it was found that, most of the producers and retailers have little or no knowledge about maintenances of quality of the Shidhil.Traditional Shidhil are stored in unhygienic condition by the retailers and marketed without proper packaging.Customized products of Improved Shidhils can be prepared of attractive color and flavor by maintaining the hygienic condition, using good quality taro and mustard oil along with different species of fishes like kachki, mola, puti or mixed species of these fishes by which percentage of protein ranges from 39.18 to 44.25.

Fish
paste covered with taro leaf and kept in dark place for 3 days for fermentation Traditionally prepared Shidhil Dried fish Shaping of Shidhil after fermentation Plate.2. Traditional preparation procedure of Shidhil.Plate.3. Traditional Shidhils collected from different districts.

Plate. 4 .
The fishes and taro used to prepare improved Shidhil in the laboratory.Preparation of taro paste (b) Mixing of fish powder and taro paste (c) Sample in giant taro leaf for fermentation (d) Mixing of turmeric powder and mustard oil to fermented sample (e) Shaping of sample (f) Drying of Improved Shidhil under the sunlight (g) Dried Improved Shidhil produced with three species of fish Plate.6. Preparation procedure of improved Shidhil in laboratory.

Table 6 . Survey result on the price, shape, weight of Shidhil and the spices used in Shidhil production in Rangpur, Kurigram, Nilphamari districts. Table 7. Organoleptic characteristics of traditionally prepared Shidhils collected from Rangpur, Kurigram and Nilphamari districts.
Proximate composition of traditionally prepared Shidhils collected from survey area is presented in Table9.The obtained results showed that, percent moisture content of Shidhils collected from Rangpus was in higher range (26.45 to 32.60) and was in lower range in Shidhils collected from Kurigram (10.96 to 17.78).On the other hand, the percent protein range was higher (42.75 to 50.83) in Shidhils collected from Kurigram and in lower range (25.49 to 38.80) collected from Rangpur.Percent lipid content was in lowest range (11.30 to 13.29) in Shidhils collected from Nilphamary district.This variation in the proximate composition among the traditionally prepared Shidhil samples of three districts of study area might be due to differences in amount of ingredients used by the local producers.