Non-irradiated Rice Research Articles

Effect of gamma-irradiation and extrusion on the physicochemical, thermal and aroma-active compounds of rice flour

Food irradiation seems to be an effective and safe method for preventing microbial and insect contamination in cereals. Interestingly, the determination of the aroma-active compounds in irradiated and extruded rice flour does not yet exist. This study aimed to investigate aroma and aroma-active compounds of non-irradiated rice flour (NIRF) and irradiated and processed rice flour (IPRF) by the SPME method combined with GC-MS-O. In the present study, twenty-three aroma-active compounds in the NIRF sample while fifteen in the IPRF sample were identified with 1.6–4.9 odor intensity scores. Hexanal [4.9], nonanal [4.4], heptanal [3.9], decanal [3.3], 3-Octen-2-one [3.1] and were detected as key odorants in all samples. Whereas, 2-penthylfuran [3.8], octanal [3.8], nonanal [4.5], and benzaldehyde [2.1] were clearly higher in the IPRF sample, considering NIRF. The amount of hexanal which can be considered as irradiation odor (IO), has been increased due to the food irradiation process.

The effect of gamma radiation on the growth of black rice plants generation m1

Black rice is a food that can be consumed as a functional food ingredient. Black rice has not been widely cultivated while the seeds are not commercially available. Besides, black rice also has several weaknesses such as longevity, high plant habitus and low production. This study aims to test black rice accession using gamma ray irradiation in the M1 generation. The research was conducted in January - April 2020 in the experimental rice fields of Cineam District, Tasikmalaya Regency. The materials used are black rice seeds (PH2, PH3, PH5, PH7 and PH8). The treatments tested were 5 black rice accession (PH2M1, PH3M1, PH5M1, PH7M1 and PH8M1) that was irradiated with gamma rays (200 Gray) and 0 Gray as control. The results showed that irradiated and non-irradiated rice growth gave different responses. All black rice accessions after irradiation experienced stem shortening and decreased number of filled grains. Accession PH 7 showed shorter flag leaves, number of productive tillers and fewer total tillers after irradiation. Meanwhile PH8 showed the number of productive tillers and total tillers were more and the panicles were shorter after irradiation.

The short-stemmed selection of M4 generation of Mentik Susu rice mutants as irradiation result with 200 gray gamma ray

This study observed the performance of mutated M4 generation of “mentik susu” rice irradiated with 200 Gy gamma ray and select the high productivity short-stemmed ones. The research was conducted in Karangpung Village, Kismoyoso, Ngemplak, Boyolali Regency. In total, 39 individual M3 200 Gy gamma ray irradiated “mentik susu” rice and non-irradiated “mentik susu” rice as control were planted. The observation was analyzed descriptively and used t-test to know the difference with the control. There were differences between irradiated and non-irradiated rice on plant height, harvest time, number of productive tillers, weight of 100 grains, and grain yield per plant. There were 25 selected mutated M4 generation “mentik susu”. Those strains were M-MS2-G15T3- 2 (5),(19),and (27), M-MS2-G15T3- 4 (7) and (28), M-MS2-G15T3- 5 (21), M-MS2-G15T3- 7 (18) and (28), M-MS2-G15T3- 8 (5), M- MS2-G15T4-24 (10), M-MS2-G13T20- 12 (17) and (27), M-MS2-G18T7- 4 (4),(5),(9), and (24), M- MS2- G18T7- 6 (19) and (24), M- MS2- G18T7- 7 (11) and (24), M-MS2-G18T7- 10 (5), M- MS2- G18T7- 11 (24), and M- MS2- G17T7- 15 (2) and (10) which were irradiated, and have short-stemmed characteristic and higher production compared to the control.

Effect of Gamma Irradiation on 2-Acetyl-1-pyrroline Content, GABA Content and Volatile Compounds of Germinated Rice (Thai Upland Rice).

Aroma intensity in rice is related to the level of 2-acetyl-1-pyrroline (2AP). The accumulation of 2AP in rice has been synthesized via l-proline metabolism by inactive betaine aldehyde dehydrogenase enzyme (BADH2), which activates 2AP accumulation. Meanwhile, active BADH2 inhibits 2AP accumulation but activates γ-aminobutyric acid (GABA) accumulation. The improvement of 2AP content in rice has been reported under certain conditions, such as high salinity, water treatment, and reduction of high intensity solar exposure. In this study, we conducted the effects of gamma irradiation on 2AP content, GABA content and volatile compounds of germinated rice (Thai upland rice). Our results showed that the GABA content was highest when rice seeds germinated within a 24-h. The 2AP content of irradiated rice (germinated within a 24-h duration) was higher than non-irradiated rice for all gamma doses, particularly at 20 Gy, which showed a 23-fold higher level of 2AP than non-irradiated rice. On the other hand, the reduction of the GABA content of irradiated rice was caused by an increase in the gamma dose. At 300 Gy, irradiated rice had a GABA content approximately 2.6-fold lower than non-irradiated rice. Moreover, we observed that a reduction of volatile compounds occurred when increasing gamma dose. However, some volatile compounds appeared in the irradiated rice at gamma doses of 60 Gy, 80 Gy, 100 Gy and 300 Gy. Furthermore, we observed that the level of Octanal, which is the compound most related to aroma intensity, of irradiated rice was stronger than that of non-irradiated rice. Our results demonstrate for the first time that 2AP and GABA contents are sensitive to gamma irradiation conditions. Moreover, the results indicate that the gamma irradiation technique can be used to improve the aroma intensity of rice.

Qualidade tecnológica do arroz branco polido submetido à irradiação gama (Co60)

A aplicação da radiação ionizante, com o propósito de garantir a segurança dos grãos, tem sido apresentada como alternativa eficaz e segura ao uso de defensivos agrícolas e prática promissora, a ser utilizada para estender a vida útil e reduzir as perdas das safras de grãos. Contudo, assim como outros tratamentos de conservação de alimentos, a irradiação pode alterar sua qualidade. Este trabalho foi realizado com o objetivo de avaliar a qualidade de cocção do arroz submetido a diferentes doses de irradiação gama Co60 (0,0 kGy, 6,5 kGy e 7,5 kGy). Observou-se que o arroz irradiado com 7,5 kGy apresentou um tempo de cozimento significativamente maior (18,21 min.) que o do arroz irradiado na dose 6,5 kGy (17,11 min) e 0,0 kGy (16,83 min.). Os valores médios de expansão do volume do arroz não irradiado foi de 365,65%; já, para o arroz irradiado, os valores foram menores, apresentando-se com 322,19%. Quanto à perda de sólidos solúveis, essa foi significativamente maior no arroz branco polido irradiado (17,0%), do que no arroz não irradiado (10,35%). Embora a irradiação gama tenha influenciado em alguns parâmetros de cocção do arroz, refletindo-se em maior tempo de cozimento, para a irradiação na dose 7,5 kGy, no menor coeficiente de expansão do volume e na maior perda de sólidos solúveis, os valores encontrados assemelham-se aos valores referenciados, na literatura, como desejáveis para a qualidade deste cereal.

Effect of high proton beam irradiation on pasting properties of rice starch

Rice seed was treated by high proton beam irradiation up to 1,200 Gy in order to elucidate physicochemical properties of irradiated rice starch. The decrease of amylose content in two rice cultivars ranged 3.5 to 3.6% compared to the non-irradiated rice under the highest proton beam irradiation (1,200 Gy). Gel consistency in japonica rice cultivar Ilpum was significantly increased with increasing proton beam irradiation. Its values approached 9.7 in the Ilpum rice cultivar and 8.7 cm in the Hanmaum rice cultivar. The peak viscosity, hot peak viscosity, cool peak viscosity, and setback were significantly decreased with increasing proton beam dose. High proton beam irradiation caused a significant decrease in the onset temperature (To), peak temperature (Tp), conclusion temperature (Tc), and enthalpy change (ΔH). Gelatinization range (R) in two rice cultivars was more broaden in higher proton beam irradiation than in low proton beam irradiation. The crystallinity degree of two rice starches irradiated with high proton beam was significantly increased and it ranged from 3.25 and 4.39% compared to the non-irradiated rice starches. It might be deduced that proton beam irradiation causes changes of starch, especially at high irradiation of proton beam.

An improved method to identify irradiated rice by EPR spectroscopy and thermoluminescence measurements

Minimal change in irradiated foods with low dose treatment makes the identification process a difficult task. Two independent physical methods, electron paramagnetic resonance (EPR) spectroscopy and thermoluminescence (TL) detection were employed for detection of irradiation treatment on Basmati rice. EPR investigation of 0.5–2.0 kGy irradiated rice samples showed a short lived, asymmetric, dose dependent spectrum ( g = 2.005), characterised by the radicals of irradiated starch. However, this signal disappears with time. The present work explores the possibility to identify irradiated rice by the relaxation characteristics and thermal behaviour of the radicals. This study reports for the first time that the different microwave saturation behaviours of the signal ( g = 2.004) in irradiated and non-irradiated rice samples provide an important clue to identify radiation treatment beyond the period when the radiation specific EPR spectral lines have disappeared. TL investigation involving scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX) of the poly-minerals isolated from the rice samples allowed to discriminate clearly between irradiated and non-irradiated samples even after a prolonged period of storage.

Changes in physicochemical and sensory-properties of irradiated rice during storage

Milled aromatic rice (KDML-105) was γ-irradiated at doses of 0, 0.2, 0.5 and 1.0 kGy. Changes in physicochemical and sensory properties were recorded during subsequent storage in polyethylene bags at ambient temperature for 1 year. Similar trends were observed in both irradiated and non-irradiated samples. Insignificant changes in yellowness and total solids in cooking water were observed during storage of irradiated rice compared with those of naturally-aged rice. Irradiated rice showed less increase in Rapid Visco Analyzer (RVA) setback, greater reduction of RVA breakdown, and softer texture than non-irradiated rice. It also had a softer but slimy texture, off odour and inferior taste compared with the non-irradiated sample. Based on overall acceptability to panelists preferring fresh rice, non-irradiated rice could be stored for more than 1 year while rice irradiated at 0.2, 0.5 and 1.0 kGy had shelf lives of 9, 7 and 2 months, respectively.

Germination test for identification of gamma-irradiated rice

Husked rice ( Oryza sativa L.) was used for the identification test of irradiation, since it grows faster than unhusked rice after 1 month of storage, and germination success is not affected by storage time and temperature. The critical dose that inhibited root elongation varied from 0.15 to 0.5kGy according to the rice cultivar. All cultivars tested exhibited similar reductions in root elongation after γ-irradiation of 0.5kGy or more. Most of the rice samples which were irradiated above 0.5kGy exhibited root growth of less than 10 mm after 3 days of incubation. The reduction was not affected so much by the presence of a husk at the time of irradiation. Storage periods of up to 12 months had little effect. This test can thus discriminate between irradiated and non-irradiated rice for 12 months or more after γ-irradiation.

Cooking Quality of Brown Rice as Influenced by Gamma Irradiation, Variety and Storage

ABSTRACTTwo long grain and one medium grain brown rice varieties were gamma‐irradiated at 1.0 and 2.0 kGy to ascertain if cooking time could be decreased and to determine effects of storage on chemical and physical characteristics. A tendency toward decreased cooking time was observed as dose level increased. Cooking time was not significantly (P> 0.05) affected by storage. A trend was noted in water uptake ratios, soluble starch of residual cooking water and volume expansion due to irradiation. Storage of irradiated rice produced similar changes to those of nonirradiated rice. Variety also contributed to differences in irradiated samples, such as cooking times, water uptake, starch retention and grain volume expansion.