Judul: Effect of parboiling and rice varieties on physicochemical and starch digestive properties of ready to eat rice
Abstrak: n recent years, people tend to consume ready to eat (RTE) rice. However, several disadvantages were encountered in RTE rice especially in texture and starch digestive properties, thus modifying the processing method is needed. This study was conducted to developing RTE rice processing using parboiling technique and to investigate the effect of parboiling and rice varieties on RTE rice in retort pouch characteristics. Brown rice grains of Pitsanulok (PSL) (29.17% amylose), Homnin (HMN) (21.22% amylose), and Sinlek (SLK) (21.91% amylose) were undergo parboiling and subsequently prepared into RTE rice packed in retort pouch. Their physicochemical characteristics, antioxidant activities, starch digestive properties, and sensory qualities were evaluated. Parboiling of brown rice gave significant changes in some physicochemical characterics including changes in moisture and ash content, decreased in hardness, adhesiveness, and lightness value. Each rice variety gave different value of physicochemical characteristics significantly. Compared to unparboiled rice samples, TPC of parboiled PSL was decreased, whilst parboiled HMN and SLK were increased. Furthermore, parboiling decreased the antioxidant capacities based on DPPH and FRAP activity methods. Rice variety of HMN has the highest TPC, DPPH, and FRAP, followed by SLK and PSL respectively. Furthermore, parboiling did not affect the resistant starch (RS) and glycemic index (GI) significantly. However, rice varieties affect the RS and GI significantly with PSL has the highest RS followed by SLK and HMN respectively (2.09-2.74, 0.38-0.60, and 0.34-0.59 g/100g sample, respectively) and HMN has the lowest GI followed by PSL and SLK respectively (83.84-89.54, 85.79-96.52, and 88.99-97.49, respectively). Based on sensory qualities, HMN-UP has the highest sensory scores compared to other products. Therefore, there was a possibility to apply parboiling technique into the specified rice variety to maintain the antioxidant, improve RS and GI, and obtain desirable sensory qualities. However, optimization of parboiling method is needed to obtain desirable results.
Keyword: Antioxidant Properties, Glycemic Index, Parboiling, Ready to Eat

Judul: Rekayasa Proses Pengolahan Beras Pratanak Untuk Memperbaiki Kualitas dan Menurunkan Indeks Glikemik pada Gabah cv. Ciherang
Abstrak: Rice milling process causes the nutrients contained in the aleuron and perikarp layer wasted and resulting high glycemic index. Foods having high glycemic index raise blood glucose level quickly, they are not recommended for consumption by people with diabetes mellitus. To provide an alternative staple food, parboiled rice could be selected. Parboiled rice processing method that has been developed in Indonesia takes a long time process, so it is necessary to find an alternative process faster and able to reduce the value of glycemic index. Parboiled process can be accelerated by soaked a few moments or even just washed, steamed with high pressure, then dried until it reaches 14% moisture content and milled. The research was aimed: (1) to study the effect of steaming pressure on physical quality, chemical composition and organoleptic properties; (2) to study the glycemic index of parboiled rice at various steaming pressure. The study was conducted using a completely randomized design with 4 treatments and 2 controls as much as 4 replications. The treatments used steaming pressure i.e 0.8 kg/cm2 (110oC), 1.5kg/cm2 (122oC), 2.0kg/cm2 (127oC) and 2.5 kg/cm2 (132oC) and controls used polished and brown rice. Parboiled rice, polished and brown rice then analyzed on physical quality, chemical composition, functional and organoleptic properties. Analysis of physical quality parameters include whole grains, heads grain, broken grains, water content and yield. Chemical composition of the analyzed parameters include moisture content, ash content, fat content, protein content, carbohydrates content, amylose and resistant starch content. Analyzed for functional properties is the glycemic index. Organoleptic test was conducted to test hedonic scale really like to strongly dislike (1-7), including color, flavour, texture and taste, of 30 untrained panelists. Data from a variety of parameters, then analyzed using the methods of data analysis of variance at level α = 5%. If there is a real difference, then followed by Duncan's multiple comparison test. The results showed that engineering of pressure parboiled rice processing, could increase physical quality i.e increased the whole grain from 63.84% to 84.55%, reduced broken from 22.65% to 7.54%, reduced small broken from 0.44% to 0.28% and increased yield from 66.01% to 72.44%. Pressure parboiled rice processing was also able to change chemical compositions i.e increased fat from 0.89% to 1.27%, increased ash from 0.57% to 0.76%, increased amylose from 30.29% to 34.5%, increased amylose resistant starch from 33.64% to 34.59%, reduced carbohydrate from 88.78% to 88.77% and reduced protein from 9.76% to 9.21%. The use of a higher steaming pressure on parboiled rice processing, could reduce the level of preferring for parameters color, arome, texture and flavor. The panelist relatively preferred of arome and texture, but rather preferred of color and flavor. Pressure parboiled rice processing with 2.0 kg/cm2 steaming pressure (127oC) could reduce the glycemic index from 48.18 to 35.52, while the steaming pressure of 0.8 kg/cm2 (110oC) could reduce the glycemic index from 48.18 to 44.88.
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Judul: Penyelesaian Masalah Pelabelan Graf vertex Magic pada Graf Cycle Sederhana
Abstrak: Graf vertex magic adalah suatu graf memiliki nilai bilangan magic yang sama pada masing-masing vertex yang berbeda. Graf cycle sederhana adalah suatu walk tertutup yang mengandung setidaknya tiga vertex, semua vertex-nya berbeda dan setiap vertex terhubungkan oleh satu edge.
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