Judul: Development of Miang Salad, A Pickled Tea Leaves Product of Thailand
Abstrak: Miang is pickled tea leaves (Camellia sinensis var. Assamica) from northern Thailand. While its taste is not well accepted, it has high antioxidant activity. Therefore, this research was aimed to develop miang salad that meets consumer’s preference. In developing this product, three studies were done. Firstly, the quality of miang was investigated. The pH of miang was 4.26±0.01, while the total polyphenol content (TPC) and DPPH radical scavenging activity were 15.14±0.37% (w/w dry basis) and 113,058.54±5,643.17 μmol Trolox/100 g dry basis, respectively. For microbiological properties, the total viable count and yeast and mold count were 2.8x105 CFU/g and 5.0x105 CFU/g. The coliform bacteria was less than 3.0 MPN/g. Secondly, suitable formulation for miang salad was studied. There were 6 formulas developed by using mixture design technique. Three miang salad contents were varied: miang (50-80%), pickled ginger (10-40%), and pickled garlic (10-40%). Sensory evaluation was conducted by using 30 untrained panelists (Mae Fah Luang University students) to evaluate the color, odor, sweetness, sourness, and overall liking of miang salad. The result showed that the best formula consisted of 50% miang, 10% pickled ginger, and 40% pickled garlic had the highest overall liking score of 6.30±1.80. Miang salad from the best formula was pasteurized at 70 oC and 80 oC for 10, 15, and 20 minutes. Pasteurization reduced the number of microbes down to <2.5x101 CFU/g (total viable) and <1.0x100 CFU/g (yeast and mold). However, heat treatment reduced the product’s lightness and antioxidant activity. Higher temperature and longer holding time produced worse effect. At 70 oC, TPC and DPPH radical scavenging activity decreased by 2.31-6.92% and 5.33-16.67%, while at 80 oC decreased by 16.14-22.22% and 41.27-49.66%, respectively. In conclusion, miang salad pasteurized at 70 oC 10 minutes was the chosen product due to its highest overall liking score and considering its microbial count, antioxidant activity, and color.
Keyword: Consumer preference, miang salad, pasteurization

Judul: Development of Mangosteen Infusion Tea (Garcinia mangostana L.) Mixed with Blueberry.
Abstrak: Mangosteen infusion tea (MIT) is a tea product consisted of dried mangosteen pericarp (DMP). MIT has an unpleasant taste but has many benefits. An alternative to increase mangosteen pericarp (MP) consumption is using salt-bitter mixture interaction by soaking in 10% salt solution and taste masking using sweet-sour flavor from stevia and blueberry. This research aimed to develop MIT mixed with blueberry to meet optimal formula and determine its quality. MIT was mixed with blueberry and the formula optimized by Mixture Design D-optimal based on the value of non-sensory responses lightness (L) and oHue of MIT blueberry was measured by Hunter La*b*, Total Phenolic Content (TPC), and sensory responses including color, blueberry odor, sweet, grouping taste (bitter, astringent, aftertaste and sour) and overall liking. Three components were constrained as DMP (60-70%), blueberry powder (20-30%), and stevia (5-10%). The result of optimal formula consisted of 64.20% DMP, 26.59% blueberry powder, 9.21% stevia with desirability value 0.858. The lightness value of optimum formula was 23.80, oHue was 261, TPC value was 3.07 g GAE/100 g. Sensory evaluation score results for color, blueberry odor, sweet, grouping taste, and overall liking were 7.62, 5.50, 6.22, 6.41, and 6.77 respectively. Total viable count and yeast & mold of the optimal formula was 6.1x101 CFU/g, and 3.2x101 CFU/g has complied with Indonesian Regular Standard for black tea in tea bag packaging. The result of sensory and consumer acceptance test showed that MIT mixed with blueberry have potential market proven by 88% of consumer accepted MIT mixed with blueberry and 77% willing to buy if it sold on the market.
Keyword: Consumer acceptance, mangosteen infusion tea, product development, D-optimal, taste masking

Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular