Effect of Parboiling on Milling, Physicochemical, and Textural Properties of Medium‐ and Long‐Grain Germinated Brown Rice

Abstract

Cereal Chem. 93(1):47-52Germinated brown rice is considered a more nutritious and palatable cooked product than conventional brown rice. However, germination usually decreases rice milling yield and alters some physicochemical properties. Parboiling is commonly used to increase milling yield and retain nutrients, but it also changes rice color and texture. The objective of this study was to investigate the effect of parboiling on milling, physicochemical, and textural properties of a medium-grain and a longgrain rice after germination at varying durations. Germinated rice samples of three germination durations were prepared with one germination time before the optimum time at which 70% of rice revealed hull protrusion, the optimum time, and one time after. Germinated rice was then immediately parboiled at 120°C for 20 min and was then immediately dried. The milling, physicochemical, and textural properties of parboiled germinated rice from both cultivars were determined. Parboiling significantly decreased the percentage of brokens, whiteness, and the apparent amylose content and increased g-aminobutyric acid content (GABA) in the nongerminated rice and rice at the first germination duration for both cultivars. Parboiling reduced pasting viscosities for both cultivars, but Jupiter still exhibited higher pasting viscosities than Wells. Cooked parboiled germinated rice was overall softer than nonparboiled rice because of kernel splitting, but Wells remained harder and less sticky than Jupiter. In conclusion, it is beneficial to combine parboiling with germination to enhance nutritional values and improve milling properties without affecting textural properties for both rice cultivars.

Comparison of germination–parboiling, freeze–thaw cycle, and high pressure processing on the cooking quality of brown rice

“…Both treated and untreated BR split along the long axis after cooking. This is consistent with previous studies which, found both medium‐ and long‐grain germinated parboiling BR split after cooking (Han et al, ). They also reported that kernel splitting by constricting swelling on the kernel surface as the endosperm swelling during cooking.…”

“…These results are consistent with earlier studies which, found that the discoloration was mainly because of maillard reaction. (Chavan et al, ; Han et al, ). Since the increased lightness of cooked BR will have a positive effect on consumer perception, FTCBR and HPPBR might be more favored than GPBR.…”

“…Parboiling is a hydrothermal treatment commonly used in rice that improve milling and cooking characteristics (Buggenhout, Brijs, Van Oevelen, & Delcour, ; Hapsari, Kim, & Eun, ). It has been shown that the combination of GP enhances nutrition properties and provides soften texture of BR (Han, Jinn, Mauromoustakos, & Wang, ).…”

Mathematical modeling and thermodynamic properties of rice parboiling

“…As regards the process of parboiling of rice, the purpose of hydration is to provide the grain moisture necessary to induce the phenomenon of gelatinization (Balbinoti, Jorge, de, & Jorge, ; Han, Jinn, Mauromoustakos, & Wang, ). The gelatinization occurs due to the combination of fundamental factors, moisture, and temperature, promoting in the grain, the irreversible collapse of hydrogen bonds between the amylose and amylopectin of starch (Buggenhout, Brijs, Celus, & Delcour, ; Oli, Ward, Adhikari, & Torley, ).…”

Effect of conventional and microwave heating on physical and chemical properties of Jasmine brown rice in various forms

“…The main reactants include protein, fat and starch, especially amylose (Mohan, Malleshi, & Koseki, 2010). Amylose is readily hydrolyzed by germination‐related enzymes, such as α‐amylase, β‐amylase and α‐glucosidase (Mohan et al, 2010; Pinkaew, Naivikul, Thongngam, & Wang, 2016) and bound to other compounds such as lipid and protein, especially by heating during parboiling and drying (Han, Jinn, Mauromoustakos, & Wang, 2016; Ramesh, Bhattacharya, & Mitchell, 2000). It was noted that the amylose content is prone to be underestimated once the amylose forms complexes with other molecules (Mohan et al, 2010).…”