Effect of cooking process on phytochemical contents and anticarcinogenic potential of Jasmine rice and Kum Doisaket rice

ผลของกระบวนการหุงต้มต่อปริมาณสารพฤกษเคมีและศักยภาพการต้านมะเร็งของข้าวหอมมะลิและข้าวกํ่าดอยสะเก็ด

Name: Yuwada Rungrote

Classification :.DDC: 615.321

LCSH: Rice -- Medical aspects

LCSH: Plant extracts

LCSH: Botanical chemistry

LCSH: Phytochemicals

Abstract: Cancer is the major cause of death in population around the world and Thailand. The new cancer patient are annually increasing. Various cancer managements such as chemotherapy, radiation and surgery, can cause side effects to patient and high expense. Nowadays chemopreventive agents from natural products including fruits, vegetables, condiments and cereals have been studied to either inhibit or prevent cancer. The chemopreventive agents can act to reduce cancer formation such as antimutagenicity, anti-inflammation and antioxidant as well as immunomodulation. Rice is an important economical plant and a main staple food in many countries. Rice contains several nutrients and chemopreventive agents such as gamma-oryzanol, phenolic acid and anthocyanins. Many rice varieties can be cultivated in Thailand. Thai Jasmine rice or Khao Dawk Mali 105 is popularly consumed in Thai population due to chewy texture and volatile aroma. Kum Doisaket is a local purple glutinous rice grown in Northern Thailand. However, most reports have concerned on the contents of phytochemicals and biological activities of raw rice, little information of cooked rice has been reported. Therefore, this study aimed to compare the effect of cooking process on phytochemicals containing in Thai Jasmine rice and Kum Doisaket rice, and to evaluate cancer chemopreventive activity of mixed rice between Thai Jasmine rice and Kum Doisaket rice. The ethanolic extracts of raw and cooked Thai Jasmine, Kum Doisaket and mixed rice between Thai Jasmine rice and Kum Doisaket at the ratio of 85 and 15 were determined. The raw purple rice extract presented higher phenolic acid, flavonoid, anthocyanins and vitamin E than raw white rice. However, white rice contained higher gamma oryzanol. After cooking, both lipophilic and hydrophilic compounds were decreased in all extracts with the exception of white rice. It increased nearly 2 time of vitamin E after cooking process. Moreover, the anthocyanins including cyanidin-3-glucoside and peonidin-3-glucoside were degraded after cooking. On the other hand, some phenolic compounds including protocatechuic acid, vanillic acid and phytic acid were increased after cooking. Furthermore, we found that raw purple rice extract exhibited higher free radical scavenging activity than raw white rice. Heat treatment reduced the antioxidant activity tested by DPPH assay and iron chelating activity. Interestingly, antioxidant activity of white rice was increased after cooking tested by ABTS assay. In case of hydroxyl radical scavenging activity, there was no significant difference between raw and cooked white and purple rice extracts. All extracts did not present mutagenicity on Salmonella typhimurium strains TA98 and TA100 in both presence and absence metabolic activation. However, all extracts exhibited antimutagenic properties, but there was no significant difference between raw and cooked rice extracts. All extracts presented very strong antimutagenicity against aflatoxin B1 and 2-amino-3,4-dimethylimidazo[4,5-f]quinolone induced mutagenesis, and exhibited moderate antimutagenicity against sodium azide. The raw and cooked purple rice extract showed mild antimutagenicity against 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide. The induction of NAD(P)H quinone oxidoreductase activity of rice extract was performed in Hepa1c1c7 cells. Only Kum Doisaket rice extract could induce anticarcinogenic enzyme activity. Although the protocatechuic acid, vanillic acid and phytic acid were increased after cooking of purple rice, NAD(P)H quinone oxidoreductase activity could not induce by these pure compounds. It might be due to either synergistic effect of crude extract or other unknown phytochemicals in cooked Kum Doisaket rice. In conclusion, purple rice exhibited higher phytochemicals and biological activity than white rice. The cooking process by an electric rice cooker could destroy some phytochemical contents and antioxidant activities but not antimutagenicity. Moreover, cooking process could induce anticarcinogenic enzyme activity in purple rice. It might be assumed that cooked rice still retains cancer chemopreventive potential. However, effect of cooking process of rice on chemopreventive activities should be confirmed in animal model.

Chiang Mai University Library

Address: CHIANG MAI

Email: cmulibref@cmu.ac.th

Name: Arunporn Itharat

Role: Chairman

Name: Rawinwan Wongpoomchai

Role: Member

Name: Klintean Wunnapuk

Role: Member

Created: 2017

Modified: 2020-01-09

Issued: 2020-01-09

วิทยานิพนธ์/Thesis

application/pdf

CallNumber: Th 615.321 Y95E

eng

DegreeName: Master of Science

Level: Master's Degree

Descipline: Toxicology

Grantor: Chiang Mai University

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