STARTER CULTURES AND FERMENTED MILK PRODUCTS

Lesson 23. MODIFIED DAHI- BHAPA DAHI AND MISTI DAHI, DEFECTS

Module 13. Dahi

Lesson 23

MODIFIED DAHI- BHAPA DAHI AND MISTI DAHI, DEFECTS

23.1 Defects in Dahi

The major spoilage of dahi is through souring or growth of yeasts and molds due to its acidic nature. The defects in dahi vary depending on the type of product (set or stirred). Table-23.1 shows causes and remedies for common defects in dahi.

Table 23.1 Common defects in dahi

23.2 Nutritive and Therapeutic Value of Dahi

Dahi contain all the valuable constituents of milk except for the changes caused as a result of heat treatment of milk, microbial growth and fermentation processes. The milk constituents are predigested by microorganisms, hence become easily digestible.The digestibility of proteins in dahi is higher due to formation of softer curd, high acidity, release of peptides and amino acids. The hydrolyzed lactose becomes more easily digested. The bioavailability of essential minerals increases. As compared to milk, dahi will have higher lactic acid , amino acids, fatty acids, bacterial cell mass, carbohydrates and certain vitamins.The status of vitamins in dahi will depend upon the starter strains employed for dahi making.

The value of dahi as the rapeuticagent in the treatment of gastrointestinal disorders and other ailments of man has been recognized in the Ayurvedic system of medicine in India quite a long time ago. The beneficial effect of dahi in the treatment of intestinal diseases may be ascribed partly to the effect of lactic acid and antibacterial substances present in them. Dahi can be safely consumed by lactose intolerant people. Lots of research works are being done on the therapeutic aspects of dahi. Dahi can significantly reduce the duration of diarrhoea in children. Dahi is also believed to improve appetite and vitality. Dahi containing probiotic bacteria is found to have Antidiabetic, Anticarcinogenic, Antiatherogenic effect. Dahi has found its applications in the cosmetic field also. It is used as a beautifying, soothing, cleansing and moisturizing agent.

23.3 Modified Dahi - Misti Dahi

Misti dahi is an indigenous sweetened fermented milk product popular in the eastern parts of the India. Misti dahi has creamish to light brown color, firm consistency, smooth texture, and pleasant aroma.Because of its brown colour as a result of caramelization of sugar during heating, it is also called Lal Doi. At present no legal standards are available for the product. However a typical composition of mishi dahi is given in Table 3.2.

Table 23.2 Composition of different grades of mishti dahi (%)

Mishti dahi production is mainly confined to household or cottage industries. Traditionally,it is prepared by boiling cow, buffalo or mixed milk with a required quantity of sugar and partially concentrated by simmering over a low fire during whichmilk develops a distinctive light cream to light brown caramel color and flavor. This is followed by cooling and culturing at ambient temperature using lactic culture and pouring into retail earthen cups and left undisturbed overnight for fermentation. When a firm body curd has set, it is stored at a low temperature (4°C) and served chilled. The manufacturing process is depicted in Fig. 23.1.

Fig. 23.1 Flow diagram for the manufacture of misti dahi

The starter cultures for mistidoi mainly comprises of combinations of Streptococcus salivarius ssp. thermophilus,Lb. acidophilus, Lb. delbrueckii ssp. bulgaricus andLb. acidophilus, Lc. lactis ssp. lactis and Saccharomyces cerevisiae. Microbiological examination of market samples of misti doi revealed the presence of yeasts such as Saccharomyces, Candida and Rhodotorula, besides the LAB like Lactobacillus, Lactococcus and Streptococcus.

The packaging of misti doi is similar to that of dahi. It is packaged in earthern ware or plastic cups with aluminium foil lids of various sizes.

23.4 Bhapa Doi

Bhapa Doi is a steamed, unsweetened yoghurt popular in Bengal . It resembles a soft cheesecake in its texture and consistency and has a mild sweet taste.

23.5 Dahi Based Products Popular in India

Dahi is consumed by large segments of our population either as apart of daily diet or as a refreshing beverage. The surplus dahi is used as the intermediate product and churned into makkhan (butter), while the liquid whey — chhach or mattha— is consumed as are freshing beverage or converted into kadhi, a spicy dish served hot with rice. Dahi is also used as a base for producing other products like shrikhand and lassi. Figure 23.2 shows some very popular dahi based products existing in different parts of India.

Fig. 23.2 Dahi based products

23.6 Conclusion

Fermented milks have been produced and consumed since ancient times in India and dahi being the most ancient has managed its popularity in Indian diet despite changing life styles and food habits with time. It is preferred over milk due to good taste, high nutritive and therapeutic value and most importantly, enhanced keeping quality than milk in a tropical climate like ours. It is being consumed as plain, sweetened or salted and spiced. The commercial manufacture of dahi started recently only and majority production is still confined to cottage industries. Lots of research works are being done and are going on on the therapeutic aspects of dahi, especially using probioticbacteria.