Foam mat drying is an economical alternative to drum, spray and freeze-drying for the production of food powders. The liquid is whipped to form stable foam, and dehydrated by thermal means. The larger surface area of the foam accelerated the drying process for the rapid moisture removal from the high moisture feed. A high-quality food powder can be obtained by the proper selection of foaming method, foaming agents, foam stabilizers, time taken for foaming, suitable drying method and temperature. In this article, the basics of foam and its structure, methods of foaming, types of foaming method and stabilizing agents for the production of stable foam have been analyzed. The influence of foaming agents and foaming properties on the drying characteristics of fruit juices are also studied. This article reviewed the application of foam drying process for different food materials, the microstructure and the quality of powders obtained by using different foaming agents. PRACTICAL APPLICATIONThe renewed foam mat drying is considerably cheaper than freeze and spray drying for the production of fruit powders. This process can be used for largescale production of fruit powders because of its suitability for all types of juices, rapid drying at lower temperature, retention of nutritional quality, easy reconstitution and cost-effective for producing easily reconstitutable juice powders. Fruit juice powders obtained through this process have high economic potentials over their liquid counterparts such as reduced volume or weight, reduced storage space, simpler handling and transportation, and much longer shelf life. The fruit powders obtained through this method can find applications in snacks, beverages, ice creams, bakery products, as a starter for the preparation of instant foods, pastes, etc.

The Box-Behnken design of experiments under response surface methodology (RSM) was used to optimize the foaming process for the development of foam mat-dried muskmelon powder. The independent variables were the concentration of egg albumen (EA), carboxymethyl cellulose (CMC) and whipping time (WT). The responses were foam density, foam drainage volume and foam expansion. The optimum conditions for foaming process were EA (11.59% w/w), CMC (0.59% w/w) and WT (3.97 min). The unfoamed muskmelon pulp took longer time to dry to the final moisture content of 2% d.b than foamed pulp. The effective diffusivity for the foamed muskmelon pulp was found to be higher than the unfoamed pulp. The unfoamed pulp resulted in a sticky and dark colored powder, whereas the foamed pulp had a free-flowing and light colored powder. The flaky and porous foam-dried product can be used as an ingredient in broad range of food products.

Journal of Nutritional Health & Food Engineeringhas been performed on the drying of banana blossoms.The objectives of this research are to:• Determine the effect of air temperature on drying time of banana blossoms• Fit the drying curves with ten mathematical models and investigate the goodness of fit• Calculate effective diffusivity and activation energy for the blossoms• Analyze the properties of the blossoms before and after the drying process Materials and Methods Drying experimentsFreshly harvested banana blossoms were procured from the local market in Perundurai. They were washed thoroughly in running cold water to remove adhering extraneous matter. The purple petals and the stamen were removed. From each clusters of flowers, the yellow tipped fronds that are responsible for the bitter flavor were separated manually. The edible portion was then washed in water and chopped into small pieces of length 1 cm. To prevent enzymatic browning and to remove the characteristic bitter and starchy flavor the blossoms were soaked in buttermilk. They were soaked in 500 ml of buttermilk for about 15 minutes. After pre-treatment the flowers were dehydrated using a traydryer. Blossoms of 500-1000 g were taken for dry drying and spread over perforated aluminum trays and trays were kept in the drying chamber. Initial moisture content was determined by the standard AOAC method [12]. The initial moisture content was found to be 87.3% (w.b.). Drying experiments were carried IntroductionBanana blossom, an agricultural by-product, is obtained from the subtropical Musa species originating from India. It is being consumed as a vegetable in the Asian countries like India, Malaysia, Indonesia, Sri Lanka and the Philippines. It has been appreciated for its nutritional content in dietary fibers, proteins, fatty acids, vitamin E, flavonoids and minerals such as magnesium, iron and copper [1]. At ambient temperatures, the blossoms bloom continuously and drop the petals. At high temperatures the flowers start rotting and chilling turns the white heart of the flowers into black. Moreover, in spite of its high fiber content blossom consumption may be restricted due to the cumbersome preparation procedures. Convenience in preparation, promotion of the intake of fiber rich vegetables and increase in shelf life can be achieved by developing a preserved product from the banana blossom.Drying is one of the techniques to develop a shelf stable and high quality products. The removal of moisture in the drying process prevents the growth of microorganisms and other deteriorative reactions. Drying induces a considerable reduction in weight and volume, minimizes packing, storage and transportation costs and as well as enables the product to be stored under ambient conditions [2]. Sun drying is one of the traditional methods used to preserve agricultural commodities in the tropical and sub tropical regions. However, hot air dry drying is the most widely used industrial method due to its uniform and rapid drying process [3]. AbstractIn this study, the ...

The effect of operating conditions such as bed thicknesses (0.075, 0.15, and 0.225 m) and air velocities (0.12, 0.24, and 0.36 m/s) of a solid-state fermenter on the structural, rheological, and pasting properties of finger millet during solid-state fermentation. Also, α-amylase activity of solid-state fermented flour was determined.Then, the breads were made from solid-state fermented finger millet flour to assess the suitability of solid-state fermented flour for bread making without adding the additives. The color and textural profiles of the bread were assessed. The results showed that the structural and pasting properties of solid-state fermented finger millet got modified due to bioconversion during fermentation. However, the color values and textural characteristics of bread made from solid-state fermented finger millet were not up to acceptable level. The study concluded that the operating conditions of solid-state fermenter affected the bioconversion. Practical applicationDespite the phytochemicals and glycemic value, finger millet flour cannot be used as such for baking without adding additives as it has low dough functional characters.So, the functionalization of finger millet can be improved by solid-state fermentation.The changes in structural characters, rheological, and pasting characters depend on the operating conditions of solid-state fermenter. So, for better bioconversion of finger millet and scale up of solid-state fermentation process, the knowledge about effect of operating conditions on modification of finger millet properties is required.

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