Improved shelf life of protein-rich tofu using Ocimum sanctum (tulsi) extracts to benefit Indian rural population.

A nutrition survey carried out in India revealed that the diets of the rural population are inadequate and deficient in most of the nutrients especially protein. India being the 5th-largest producer of soybean, a protein-rich cereal, can redress protein-energy malnutrition through diversification of soybean uses by developing high-value and health-based food products. Tofu, a nonfermented soybean product rich in high-quality protein, B-vitamins, and isoflavones, could be an excellent substitute for meat in Indian recipes. Tofu being rich in protein has a very short shelf life. Hence an attempt was made to improve the shelf life using extracts of tulsi (Ocimum sanctum) commonly available in rural areas. Tofu was prepared traditionally using MgCl(2):CaSO(4) as coagulating agents. Aqueous extract of Ocimum sanctum (tulsi) was added during the preparation and storage of tofu to prolong its shelf life. Water used in this study was free from microflora, plant extract used contained mesophilic count of 2.527 x 10(4) CFU/g, and no yeasts and molds were detected. Tofu with tulsi extract had 76.4% moisture and was softer than control. Not much difference in mesophilic count was observed between control and treated samples during storage; however, treated tofu was organoleptically good until the end of the study with less lipid-peroxidation and exhibited 50% (4.7 units) less protease activity than control (9.6 units) after 7 d. By using extracts of naturally available, easily cultivable tulsi, the shelf life was successfully extended to 7 to 8 d from 3 to 4 d of normal storage without refrigeration.