Analyzing the Characteristics of Roasting Process for Chinese Rice Wine by Fluidized Bed Using Superheated Steam

Abstract

Roasting with superheated steam as the medium are used to obtain gelatinized rice for "green" Chinese wine brewing. The microstructure, pasting properties and starch crystal of rice are determined. That can learn the change in rice during the roasting process is considered the basis to optimize the operating parameters and enlarge the fluidized bed. It is found that the whole process can be divided into two stages, i.e., heating and puffing, with their demarcation point occurs at 20 seconds to 25 seconds after the rice is heated. Heating is a key stage of the processing that is characterized by rapid heat transfer and significant changes in the molecular structure of rice.The temperature of the rice starch needs to be controlled to prevent thermal decomposition and abiotic browning at puffing stage. Through numerical simulation analysis of rice temperature changes in the roasting process, it was found that the two stage strategy is the best mode of roasting process, and standard temperature control curve was put forward as rice temperature control reference during roasting. The comparison between air and superheated steam as two different media shows that the gelatinization effect of rice is practically the same given the same fluidized state, although superheated steam exhibits a slight advantage.Keywords: roasting, process analysis, gelatinization, superheated steam, fluidized bed, numerical simulation, temperature control curve IntroductionObtaining a high gelatinization ratio of rice was a new application of roasting technology, which has been applied in Japanese sake and shochu production (Beizhao, 1997). Rice was heated by hot air in the fluidized bed, and then used in winebrewing after complete gelatinization. In China, researchers have carried out some attempts to apply roasting to Chinese rice wine brewing (Zhu et al., 2004;Zhang et al., 2005;Peng et al., 2002;Mao et al., 2007). It was supposed that brewing using roasted rice could not only eliminate the problem of soak wastewater, but also add a new flavor to rice wine (Zhang et al., 2005;Peng et al., 2002).During roasting, air was the most common heating medium, but would cause many problems, primarily the energy waste and environmental pollution caused by exhaust emission as well as the oxidation of materials. Superheated steam can be used as an alternative to air. Using superheated steam can condense and recover the residual heat, without polluting the environment. Since there was no oxygen in superheated steam, it would not oxide the materials. Thus, superheated steam was an ideal heating medium (Taechapairoj et al., 2003;Soponronnarit et al., 2006;Pronyk et al., 2004;Ono, 2008;Mujumdar, 2006). For this reason, we have made a series of studies on the use of superheated steam for roasting rice, and had been published (Chen et al., 2012).It can be discovered from the analysis, the obtained results and the comparison with other research results, that there were two problems blocking the industrialization of roasting technology.Firstly, browning and ca...

Effect of baking technique for rice wine production and the characteristics of baked rice wine

“…After being treated at 170 °C, the peak strength and position of the diffraction pattern of starch changed greatly, and the peak shape showed a little dispersive characteristic, especially in BR3, which indicated that the starch crystallinity decreased. This showed that the two‐stage roasting strategy was the best processing mode considering the gelatinization effect of rice 27 . However, it was important to prevent the side effects of browning and carbonization induced by persisting high temperature in the late stage.…”

“…However, it was important to prevent the side effects of browning and carbonization induced by persisting high temperature in the late stage. When baked at over 200 °C in a preliminary experiment, the inside of the rice would be too hot, which had a risk of browning 27 . Furthermore, under normal storage conditions, the moisture content of rice is about 13–15%.…”

Influence of thermal treatment on Anthocyanin, total phenolic content and antioxidant capacity of Pigmented Maize (Zea mays L.)

“…Roasting induced modification in the proximate composition and biological properties of the coffee bean, supporting the release of derivative antioxidants (13). Roasted rice wine had a better flavour compared to unroasted rice wine (8). Rice powder had decreased levels of free amino acids by roasting at high temperatures and extended duration (14).…”

“…Roasting involves applying dry heat to change the physicochemical, nutritional and phytochemical properties of raw material (7). It is one kind of thermal treatment widely applied in grain processing to improve nutritional bioavailability, phytochemical efficiency, organoleptic property and deduct the toxic components (8). The roasting of maize grains improved aroma, antioxidant capacity, food quality of semi and final products (9).…”

Effects of roasting conditions on anthocyanin, total phenolic content, and antioxidant capacity in pigmented and non-pigmented rice varieties

“…The roasting process consists of grain drying, heat application, and is usually followed by grinding into powder, with improvement in the sensory quality of traditional food preparations (Chen and Yan, 2016;Fikry et al, 2019). In addition, the process has sometimes been suggested to increase nutrient bioavailability in some foods.…”