Introduction

In the modern world fermentation technology is used for large scale culture of microorganisms which can be used as a direct source of high protein food, and is known as single cell protein (SCP). Suitability of SCP for feeding human beings has been studied by Kacmpfel et al., (1995)⁴. An obvious use of fermentation technology is processing of byproducts (waste products) obtained from industrial and agricultural products. In the present investigation okara was used, which is a byproduct of soymilk industries. The high moisture content of okara makes it unsuitable to be utilized (Shurtleff and Aoyagi, 1979)¹⁰. However, nutritional composition of okara favours its utilization. It contains 76.6% moisture, 19.91% protein, 8.37% oil, 9.53% carbohydrate and 2.82% starch. Major minerals like calcium, iron, copper and zinc also increases its nutritive value.

Okara has been used by various investigators for producing different fermentation products. Fujiwara and Takemoto (1996)² studied the composting method for tofu refuse (okara), using an air tight composting plant. Matsuo, M. (1997)⁶ has reported the in vivo antioxidant activity of okara by A. oryzae. Fuh-Juin Kao et al., (1998)³ has reported the fermentation of okara by lactic acid bacteria, with the addition of molasses and macerating enzymes. Miyamura et al., (1998)⁷ examined the fibrinolytic activity of natto produced from okara fermented with Bacillus subtilis. A process was developed for preparing better quality soymilk and okara by Nishimura et al., (1998)⁸. Kinoshita et al., (1985)⁵ has used okara for the production of riboflavin and lipase. Sawano (1999) has developed a process for producing functional okara milks and functional tofu from okara. Yousufi et al., (2003) produced SCP using okara, by controlling its moisture content.

Taking the above evidences into consideration, an attempt was made in the present investigation to produce SCP by using okara and analyse its carbohydrate content.

The production of okara and soymilk is described in Figure 1. Okara and wheat grits were mixed in three different ratios to produce the following three combinations.

Scheme 1 Click here to View Scheme

Table 1 : Combinations of Okara and wheat grits

The combinations of Okara and wheat grits were filled in petriplates, which were autoclaved. The combinations were then inoculated with two food fungi viz. R. oligosporus and A. oryzae respectively. The inoculated combinations were thereafter incubated until white cottony mycelium is produced on them. After this samples were removed from each combination and analysed for the total carbohydrate content. The total carbohydrate content was determined by AOAC method (1984).

The total carbohydrate content in different combinations, in case of R. oligosporus and A. oryzae are given in Table 2 and 3 respectively.

Table 2 : Total carbohydrate content in the three combinations with R. oligosporus

Table 3: Total carbohydrate content in the three combinations with A. oryzae

The results in the Table 2 depicts that the combination of 3 parts of Okara and 1 part of wheat grits contained maximum carbohydrate content (4.98%), with R. oligosporus. The results in Table 3 depicts that the combination of 3 parts of Okara and 1 part of wheat grits contained maximum carbohydrate content (5.02%), with A. oryzae. Hence, the combination ratio 3;1 shows maximum carbohydrate content for both R. oligosporus and A. oryzae.

Acknowledgement

The authors are thankful to the authorities of Saifia College of Science and Education, Bhopal for providing laboratory and library facilities during the tenure of the present investigation.

References

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