Microstructure and texture of khoa and gulabjamun made from cows' milk: Heat‐induced changes during processing and frying

Abstract

Scanning and transmission electron microscopy was carried out to study heat-induced structural changes that occur during the processing of khoa (a heatdesiccated Indian milk product) and gulabjamun (a product obtained by frying khoa, admixed with starch, in clarified butterfat and subsequently soaked in 60 % sugar syrup). Constant boiling of milk during khoa manufacture led to the formation of casein-whey protein complexes, which coalesced gradually on the progress of boiling, forming a fuzzy-agglomerated mass and finally precipitated as heat-induced milk gels, joined together by thick protein bridges. Further heat desiccation of this gel resulted in the compaction of the protein agglomerates with reduction in void spaces and fat globules interspersed in between (ie khoa). Frying of khoa in clarified butterfat resulted in the enlargement of the voids, producing a loose matrix having starch particles interlinked loosely with the agglomerated protein bodies and the clumped fat globules cemented in it (ie gulabjamun). The laboratory and market gulabjamun had significant structural similarities in the fat and protein moieties but differed markedly in the textural values, probably due to the differences in the chemical composition and typical structural manifestations of the starchy materials in the market gulabjamun. Composition and texture can be explained by the microstructural attributes for both khoa and gulabjamun.

Development of Gulabjamun by incorporating the Amaranthus hypochondriacus L. (Rajgara)

“…The rate of addition of Amaranthus had no significant effect (P<0.05) on peroxide value. Published data on proximate composition of gulabjamun affected by addition of Amaranthus are not available for comparison, however the values observed in the present study are very close to those reported by Sharma and Zariwala (1978) [10] ; Minhas et al (1985) [11] ; Prajapati et al (1991) [12] , (1992) [13] ; Deshmukh et al (1993) [14] ; Adhikari et al 1994 [15] ; Thakar et al (1994) [16] ; Chaudhari (2016) [17] . In product development process, sensory quality plays a vital role in deciding the acceptability of the product.…”

Effect of ingredients and processing parameters on the sensory, instrumental colour, texture and microstructure of Pinni

“…The gritty, loose matrix of coagulated milk protein vanished completely during patting stage. Similar studies on gulabjamun (a product obtained by frying khoa, admixed with starch, in clarified butterfat and subsequently soaked in 60 % sugar syrup) also shows frying of khoa in clarified butterfat resulted in the enlargement of the voids, producing a loose matrix having starch particles interlinked loosely with the agglomerated protein bodies and the clumped fat globules cemented in it (Adhikari et al 1993). Structural features of khoa were studied by light microscopy and electron microscopy.…”

“…Researchers utilized this advanced instrument to study the surface topology of Indian milk product, such as cow and buffalo milk rasogolla (Adhikari et al 1992), khoa ( Patil et al 1992 and Cham -cham (Puri et al 2016) -----etc. Adhikari et al (1993) while studying the microstructure of Gulab Jamun observed that frying of khoa in clarified butterfat resulted in the enlargement of the voids, producing a loose matrix having starch particles interlinked loosely with the agglomerated protein bodies and the clumped fat globules cemented in it (i.e., gulabjamun). Scanning electron microscopy (SEM) has been a useful tool for investigating the microstructures of cereal grains, wheat flours and derived products (Fannon et al 1993;Gallant et al 1997).…”

Principal Component Analysis for Textural Properties of Selected Blood Curd

“…The a* value has a negative correlation with the sensory score of color, indicating that the consumers preferred the pig blood curd, which has a redder appearance. Adhikari (1993) thought the arrangement and network of microstructure or macrostructure of the constituents in food caused in processing were closely related to food texture and rheological property. Anne-Marie (1982) found that the water binding decreased with an increased degree of aggregation, resulting in a coarser network with larger pores.…”