Effect of Incorporation of Fruit Powders in Instant Biscuit Mixes

Mango and pineapple powders were prepared for the processing of fruit powder based instant biscuit mixes and standardised using various levels of fruit powders (10-50%) with other ingredients. The mango and pineapple powders at 30g were taken as optimum level for processing the biscuit mixes. The processed mixes were stored in different packaging materials and stored at room temperature for 270 days. The chemical characteristics and microbial load were observed during storage period. Moisture, vitamin C contents were slightly high in pineapple powder based biscuit mixes whereas reducing and total sugars, protein, fat and beta carotene were more in mango powder based biscuit mixes. A minimal increase in microbial population was observed in all the stored samples during the study period. The organoleptic scores of the biscuit mixes were found to be highly acceptable upto 270 days

Fruit Processing industry has been termed as a "Sunrise Industry" and several efforts have been made in the last few years to give a big thrust to this sector. Fruits are important nutritional requirements of human beings, as these foods not only meet the quantitative needs to some extent but also supply vitamins and minerals to improve the quality of diet and maintain health. In view of importance of fruits in human diet, there is a need to explore ways for preserving fruits during the peak season to make them available throughout the year and minimize losses. One of the possibilities is the conversion of fruits into various stable processed products, juices, concentrates and powders. The powder of ripe fruits is sweet and has pleasant flavour with high nutritive value. Fruit powder can be used as a ready to drink product or as a flavouring material for beverages, dairy, noodles, and bakery and confectionery products. Fruit powders offer distinct advantages over the concentrated ones because they represent the ultimate in concentration and offer convenience, versality and storage stability without refrigeration. The convenience of powders outweighs the additional expense of production, packaging and transport for retail products. The introduction of fruit powder for new product formulations viz, instant mixes helps in providing new areas to utilize the fruits and helps in development of new foods for the fast moving generation.

Materials and Methods
"Totapuri" and "Giant Kew" variety of mango and pineapple were selected for the preparation of fruit *Corresponding author email: saradhavasan_ms@yahoo.com powders. The procedures for the preparation of mango and pineapple powders are given in Fig 1. Mango and pineapple powders were incorporated at different levels viz., 10, 20, 30, 40 and 50 percent with maida for the preparation of instant biscuit mix. The weighed quantum of maida was thoroughly mixed with each fruit powder (mango and pineapple) in a stainless steel vessel using a ladle, followed by the addition of powdered sugar. The leavening agent was added with constant stirring. For uniform mixing, the processed instant biscuit mix was thoroughly sieved (BS 80 mesh). The control biscuit mix was prepared by following the steps mentioned above without the addition of fruit powder. The proportion of ingredients used for the fruit powder based instant biscuit mix is given in Table 1. The biscuits were prepared from mango and pineapple powders incorporated instant mixes (10,20,30,40 and 50 %) were tested for consumer acceptability and compared with control. The fruit powder incorporation upto 30% in biscuits had good quality characteristics and the consumer scores were similar to control. Hence the incorporation level of 30 per cent was selected for both mango and pineapple powders for preparing instant biscuit mix. The physical and chemical characteristics of fruit powders were analysed. ( Table 2 &3) The developed fruit powder based instant mixes were packed in packaging materials (Metallised Polyester Polyethylene Laminated pouches (P1), 400 G Polyethylene covers protected by MPP (P2) and MPP pouches stored in plastic containers (petjars) (P3)) in duplicate and stored at room temperature for conducting storage studies for 270 days. The chemical characteristics viz., moisture (AOAC, 1995) acidity and pH (Saini et al.2000), reducing and total sugars (Ranganna,1995), protein (Lowry et al, (1951) fat (ISO,1973), beta carotene, vitamin C, (AOAC, 1995) were analysed before and during the storage period at regular intervals. Microbial load of the fruit powder based instant mixes was enumerated by the method described by Istavankiss (1984). The data obtained were analysed statistically by Completely Randomized Block Design as per Panse and Sukhatme (1967). The organoleptic scores of the biscuits from fruit powder based instant biscuit mixes were carried out on 4-1 hedonic scale by a panel of fifteen untrained judges according to the method Amerine et al (1965).

Results and Discussion
Physico chemical characteristics of fruit powder. The physical and chemical compositions of mango and pineapple powders were given in Table 2&3.The prepared mango and pineapple powders had good Table 1. Proportion of ingredients used for the fruit powder based instant biscuit mix cent acidity whereas the pine apple powder contained 1.10 per cent. The protein and fat content of mango and pineapple powders were 3.5, 2.5 and 2.6 and 2.2 per cent respectively. The TSS of mango powder was the highest with 42 0 bx followed by pineapple powder (35 0 bx). The reducing and total sugar contents of fruit powder were 5.10 and 31.90 (mango) and 3.50 and 25.80 (pineapple) per cent respectively. The reducing and total sugar contents of mango were 13.0 and 28.50 per cent. (Kalalingam, 2003). Bhaskar et al. (2003) prepared banana powder from ripe banana pulp having moisture content 6.78 per cent, pH 5.25, acidity 1.5 per cent (as per cent citric acid), ascorbic acid 56.7mb/100g, total sugar 65.87 per cent, protein 4.14 per cent, fat 0.75 per cent and ash content 2.84 per cent. The fibre content of mango powder was high (6.50%) compared to pineapple powder ( 3.50%)The beta carotene contents of mango and pineapple powders were 3120 and 20 μg/100g respectively. The  carotene content of Dashehari variety of ripe mango powder was 1855 μg/100 g (Sagar et al., 2000). The vitamin C contents of mango and pinapple powder Control 0 Fruit Powder Based 1 were 520.0 and 75.20 mg/100g respectively. Ramteke et al (1999) indicated that drum dried mango fruit powder retained more ascorbic acid and  carotene.

Chemical changes in the fruit powder based instant mixes during storage period
Moisture: The hygroscopic nature of fruit powder might be due to the absorbed moisture during the storage period irrespective of the packaging flavor, taste and colour of the respective fruits. The fruit powders were found to be pale yellow and opaque yellow. The texture of the powders was free materials. The samples stored in MPP (P1) without protection had slightly higher moisture content followed by P and P irrespective of the treatments.

Table 2. Physical characteristics of mango and pineapple powders
The actual per cent increase in the moisture content of the samples ranged between 0.68 and 0.98 (T0), 0.75 and 1.22 (T 1 ) and 1.37 and 1.5% (T 2 ) during storage. Chitra (2000) reported that moisture content in banana based weaning mix was 7.0 per cent.
Acidity: The T2 sample contained slightly higher flowing and fine. The moisture and pH content of pineapple powder were found to be more than the mango powder. Mango powder recorded 0.90 per Table 3. Chemical composition of selected fruit powders (100g) (DWB) acid content than the control throughout the study period irrespective of the packaging materials. Significant increase in acid contents of fruit powder based instant biscuit mixes were observed between treatments, packaging materials and storage. Similar result was quoted by Kala lingam (2003).
pH : A gradual decreasing trend in pH was observed in fruit powder based instant biscuit mix during storage. The sample (T2) had low pH before and after storage when compared with T 0 and T 1 samples.
Total Sugar: Among the freshly prepared biscuit mixes, mango powder based mix (T1) had the maximum total sugar content followed by pineapple powder based biscuit mix (T2) and control (T0). The reduction in total sugar content was observed throughout the storage period may be due to the  utilization of sugars in non enzymatic browning reaction occurring during storage.

Reducing sugar:
The conversion of total sugar to simple sugar during storage might have  Carotene: The composition and type of the fruit powder selected for preparation of instant mixes had influence on the  carotene content of the processed mixes. The mango powder based increased the reducing sugar level in the stored instant biscuit mixes. Similar to this the fruit powder based instant biscuit mix had higher reducing sugar content.

Protein:
The mango powder based instant biscuit mix had slightly higher protein content before and after storage than T2 and T0. The fruit powder Table 5. Changes in microbial population of the fruit powder based instant biscuit mix during storage Bacteria (10 6 /g) Fungi (10 4 /g) Yeast (10 5 /g) instant mixes (T1) had higher  carotene content than pineapple powder based instant mixes. (T2).The losses were significantly affected by the type of package as well as by the source of powder. The per cent loss of  carotene was significantly lower in P3, than P 2 and P 1 , which was due to the permeability of packaging materials to oxygen and light.
Vitamin C: Among the fruit powder based instant biscuit mixes, the pineapple powder based instant mixes showed the highest vitamin C content followed by mango powder based instant mixes. The incorporation of fruit powders in the control recorded zero vitamin C content. The vitamin C content of freshly prepared fruit powder based instant biscuit mixes was found to be 3.60 (T1) and 10.20 (T2) mg/100 g which was reduced drastically to 2.30, 2.63 and 2.71 and 6.25, 6.35 and 6.48 mg/100 g in 1 1 T , T for P , P , and P respectively at the end of the 1 2 1 2 3 1 3 based instant biscuit mix exhibited a very slight reduction in the protein content during storage period.

Fat:
The fat contents of the fruit powder based instant biscuit mixes was slightly reduced at the end of the storage period. The mango fruit powder based instant biscuit mix recorded slightly higher fat content initially and finally than T0 and T2.
storage. The initial  carotene contents of mango and apple based eggless cake mixes were 1350.96 and 10.80μg/100g which were reduced to 1246.48 and 8.24μg/100 g packed in MPP pouches at the end of storage period.(270 days) (Kalalingam, 2003). Similar trend of reduction in  carotene content was observed in the present investigation too.
A significant difference in the moisture, acidity, pH, total and reducing sugars, protein, fat,  carotene and vitamin C contents of fruit powder based instant biscuit mixes were observed between treatments, packaging materials and period of storage.

Microbial population of fruit powder based instant biscuit mix
An increase in microbial population of fruit powder based instant biscuit mix was observed as the storage period increases in the selected samples. After 270 days the bacterial population of the treated samples was slightly higher than control whereas yeast and fungal population were more or less equal in all the samples. The final bacteria, fungal and yeast counts of fruit based instant cake mix were in the range of 2.0-6×10 6 , 2.0-4.0×10 9 and 2.0-4.0×10 5 cfu/g at the end of 270 days (Kalalingam, 2003). The microbial population of the fruit powder based instant biscuit mixes showed similar picture. Though the microbial population of the instant biscuit mixes had increased during the storage period but it was within the acceptable limits, So it was highly acceptable for consumption.

Quality analysis of the prepared biscuits from fruit powder based instant mixes
The sensory attributes such as colour, appearance, flavour, texture, taste and overall acceptability of the biscuits did not show much difference between the initial and the final score values packed in different packaging materials. From the data on the organoleptic evaluation of the prepared biscuits indicated that mango powder biscuits were highly acceptable than control and pineapple powder based.

Conclusion
Highly acceptable instant biscuit mixes could be prepared by incorporating the fruit powders (mango and pineapple) upto 30 per cent. There was negligible change in the acidity, pH, total and reducing sugars, whereas a notable change was observed in moisture,  carotene and vitamin C irrespective of the fruit powder based instant mixes during storage. Among the packaging materials, MPP pouches kept in plastic containers was found to be the best. A negligible change in microbial load was observed in all the stored samples during the study period.