By: Christopher Kavimani*
If rice is cooked in milk, starch and milk, the reaction results into a thick product, which is very popularly known as kheer in India. Kheer is also known as Payas or Payasam in many parts of India. It is an extremely popular rice based heat concentrated and sweetened dairy. It is a form of sweet dish commonly known as rice pudding in the United States and Europe.
Conventionally, it is prepared by concentrating milk with simultaneous cooking of rice in an open pan over low fire and addition of sugar towards the end of cooking. In many cases, dry fruits are added to make it nutritionally rich. At present, kheer production in the organized dairy processing sector of India is very limited and close to negligible. But, considering the nutritional value of kheer, its organized production has a lot of potential / scope. Various studies have been conducted to standardize and optimize the mechanized production of kheer and related products. In addition, studies on extended shelf life of kheer and kheer ready mix have also been reported in literature.
Sensory and textural properties of Misti Dahi as affected by dietary fibres were reported by Raju and Pal (2014). Texture and Sensory are very important quality attributes of all foods for consumer acceptability. In present communication, the influence of total solids (25.1 to 45.3 %) on textural andsensory characteristics of kheer, has been evaluated. It will be helpful in deciding the total solids of the kheer, the characteristics of which may be used to design process equipments including metering and filling systems for the organized and hygienic preparation, packaging and distribution of kheer.
Materials and Methods
Raw material Basmati rice was procured from the local market, Karnal, Haryana, India. It was then cleaned to remove all sorts of foreign objects and stored in an airtight container until use. Fine granulated white sugar was also procured from the local market, Karnal. Fresh cow’s milk was procured from the Experimental Dairy, ICAR-NDRI, Karnal.
Preparation of kheer:
Kheer was prepared by cooking of rice in fresh cow’s milk by standard method steam jacketed kettle.
Basmati rice (2.5 % w/w of milk taken) was soaked in water at room temperature (rice: water as 1:2) for 30 minutes. The soaked rice was added to fresh cow’s milk and brought to boil with continuous agitation of the mixture. The boiling temperatures simultaneously cooked the added rice as well as concentrated the mixture (milk concentration). A digital thermometer (Make: Mextech, China; Range: -50°C to +150 °C; least count: 0.1 °C) was used to monitor the temperatures achieved during cooking. Two Refracto-meters (Make: Erma,Tokyo, Japan; Range 0 to 28 °Brix and 28 to 62 °Brix; Least count: 0.1 °Brix) were used to measure the total soluble solids content in the rice-milk mixture. Finely granulated white sugar (5 % w/w of milk taken) was added after the mixture attained suitable levels of concentrations. Kheer, thus, prepared was stored in covered stainless steel vessels and cooled in a refrigerator (Make: Whirlpool, India). Kheer was prepared at different levels of total solids (25.5-45.1 %) in individual batches. Total solids and bulk density of kheer Total solids content of various batches of kheer was determined employing the standard gravimetric method for sweetened condensed milk (FSSAI, 2012). Bulk density of various batches of kheer was determined by employing the standard method for milk powders (FSSAI, 2012).
Textural characteristics of kheer Textural characteristics of kheer were determined using a texture analyzer equipped with a load cell of 25 kg and a cylindrical probe (P/25) supplied with Texture Exponent Programs used this method to determine textural attributes of starch based dietary fiber systems. The kheer samples were filled into cylindrical glass beakers of 30 mm diameter and were allowed to attain room temperature. This was compressed by the probe at a control force of 5 g at the speed of 1 mm/s. Firmness, work of adhesion, work of shear and stickiness of the kheer samples were determined. The P-75 probe was used to determine the hardness of cooked rice grain. A total of 10 cooked rice grains per batch of kheer were used. During measurements, speed of the probe was fixed at 0.5 mm/s and deformation was carried to 80 % of total strain. Sensory characteristics of the kheer A 9-point Hedonic scale (9 for ‘liked extremely’ and 1 for ‘disliked extremely’) was used for the determination of sensory characterestics of the kheer by a trained panel of judges selected based on the discriminative test of sensory evaluation (Gupta, 1976). They evaluated the product for various sensory parameters e.g. colour and appearance, flavour, consistency, mouth feel and overall acceptability.
Analysis of variance (ANOVA) for different characteristics of kheer was carried out by using PROC ANOVA procedure (SAS software, version 9.3). Microsoft Excel-2007 software was used for creation of 2D-graphs of various textural characteristics such as work of shear, firmness, work of adhesion, stickiness of kheer and hardness of cooked rice grain. The second order polynomial (quadratic) regression equations were also obtained using Microsoft Excel-2007 software for prediction of work of shear, firmness, work of adhesion and stickiness of kheer and hardness of cooked rice grain.
Milk and milk products have been acknowledged for long, as an important constituent of a balanced diet. It is an optimally rich source of vital nutrients such as proteins, fat, lactose, vitamins, minerals, enzymes, hormones, immunoglobulin and cells. Milk and milk products are consumed not only for meeting the nutritional requirements of the consumers, but also for their role in preventing various disorders. One of the healthiest and tastiest ways to take the goodness of milk can be kheer. The hydro-thermal processing of rice has become one of the most widespread food industries of the world since it constitutes a major part of the global nutritional need for carbohydrates.
Senior Process Engineer-TetraPak*