Puffed rice: A materialistic understanding of rice puffing and its associated changes in physicochemical and nutritional characteristics

Abstract

Puffed rice is an expanded breakfast cereal obtained by high temperature short time heat treatment of salt‐treated parboiled rice. This intense heat results in deformation and phase transition within the grain and delivers an expanded porous structure. Such transformations essentially govern the final puffed rice quality and its physicochemical attributes. They commence during pretreatment and proceeds till puffing. These properties of rice such as expansion, hardness, degree of gelatinization, glass transition temperature, crystallinity, color, nutrient content, porosity, and microstructure are altered during the processing of puffed rice from pretreated parboiled rice. This review attempts to address such materialistic changes in the rice matrix during puffed rice production that would help a researcher to understand the associated changes in physicochemical and nutritional characteristics. Practical applications Studying the changes in the material properties associated with processing conditions is a useful approach to understand final quality of puffed rice. The review is a detailed study of parameters like expansion, hardness, degree of gelatinization, glass transition temperature, crystallinity, color, nutrient content, porosity, and microstructure that influence the final product characteristics of puffed rice and help a manufacturer to produce an acceptable product by exercising strict control on them. Insight on changes brought about by alteration in these characteristics are thus of paramount importance. This is because it can help individuals to produce puffed rice of optimized quality, correct product defects, and cause alterations in the end‐product. Researchers working on possible future applications can have a thorough background knowhow. Thus, the work would bear extreme commercial and scientific importance.

Effect of Sand-Frying-Triggered Puffing on the Multi-Scale Structure and Physicochemical Properties of Cassava Starch in Dry Gel

“…At the heating stage, the surface temperature of the gel did not reach its glass transition temperature ( T g ) ( Figure S2 ), so the gel could not be puffed. It has been proven that a phase transition from a glassy state (rigid) to a rubbery state (soft) was necessary for material expansion [ 34 ]. In addition, there was not enough pressure to expand the gel since the water remained largely unevaporated.…”

“…This caused the changes of the physical characteristics, and the evolution of textural properties could be attributed to the porous structure of the gel upon sand-frying as this structure required only a low force to break it [ 35 ]. In addition, this porous structure enhanced the light flux, which increased the whiteness of the gel [ 34 ].…”

Considerations for improvising fortified extruded rice products

“…SME also controls expansion in puffed products. This may be due to increase of gelatinization (Meng et al., 2010), which is an important factor controlling expansion and the degree of expansion directly impacts textural attributes in such products (Saha & Roy, 2020b). Incorporation of proteins in feed decreases crispness due to compression in bubble growth inside a denser matrix (Dalbhagat et al., 2019).…”

“…The final expansion in extruded products was found to be dependent on the combined effects of feed composition and processing parameters (Beck et al., 2018). Degree of starch gelatinization is also responsible for causing expansion in puffed products (Saha & Roy, 2020b). Expansion on the other hand is inversely related to bulk density.…”

Comparative study of the effects of thermal blanching pretreatments and puffing temperature levels on the microstructure and qualities of crisp banana slices

“…This puffing technique usually operates at temperatures in the range of 160-220 C with a short duration time of 1.5-2.5 min (Hofsetz, Lopes, Hubinger, Mayor, & Sereno, 2007;Raikham, Prachayawarakorn, Nathakaranakule, & Soponronnarit, 2013;Tabtiang, Prachayawarakorn, & Soponronnarit, 2012). During this processing, food is subjected to high temperatures of puffing medium, and the food temperature rapidly rises, resulting in the phase transition from a glossy to a rubbery state for starchy food and the flash evaporation of water inside the food structure (Saha & Roy, 2020;Wu & Schwartzberg, 1992). These phenomena allow the food volume to suddenly expand, thereby creating greater porosity in the internal structure of food (Hofsetz et al, 2007;La Fuente & Lopes, 2018).…”