Judul: Effect of CaSO4.2H2O (coagulant) concentration and temperature on the protein coagulation process and curd texture
Abstrak: Texture is an important aspect to determine consumer preferences for products based curd, one of them is tofu. Differences in texture of are influenced by the parameters of the coagulation process which consists of coagulant concentration and coagulation temperature. Effect of differences in coagulation parameters was represented by the data of whey transmittance, whey protein content, pH value of whey, curd protein profiles, moisture content and total solids of curd, and curd texture (objectively by TPA devices). This study used CaSO4.2H2O as a coagulant for soybean milk with the concentration of 0.015 N (A), 0.030 N (B), and 0.045 N (C). Soy milk was coagulated at the temperature of 60 and 80°C. Coagulation produced curd tofu and whey. The data suggest that whey C had the highest transmittance [23.52% (60°C) and 19.30% (80°C)], whey protein B had the lowest [0.448 mg/mL (80°C) and 0.390 mg/mL (60°C )], while the whey pH values were not significantly different in the range of 5.72 to 5.90. The curd C had the highest moisture content (wet basis) [20.63% (80°C) and 18.69% (60°C)] and the highest total solids/yields (raw material basis) [40.88% (60°C) and 37.75% (80°)]. The function f(x) = y = 2.896x + 1358 was obtained to correlate the curd texture by objective measurement (x) and the sensory evaluation (y). Curd C (80°C) had the highest hardness 2.474 (slightly hard) while the curd A (60°C) had the lowest hardness 1.164 (soft). Meanwhile, the curd protein profiles consists of 7S globulin (β-conglycinin) and 11S globulin (glycinin) protein subunits. The 7S protein consists of subunits α, α’, and β, while the 7S protein consists of the acid subunits (A1, A2, A4, A6) and the base subunit. Percent of 11S subunits in the curd increased with increasing concentration of coagulant in all the coagulation temperature. The percent of 7S subunits indicated otherwise, as well as its components, α+α’ and β. Overall, subunits of proteins that have an influence on the texture are the A1 subunit and the base subunit of the 11S proteins with the highest Pearson correlation on the curd cohesiveness.
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Judul: Pengaruh Umur Koagulan Whey Tahu dan Suhu Awal Proses Koagulasi terhadap Pola Elektroforesis Protein Terkoagulasi dan Mutu Tekstur Curd Kedelai (Glycine max)
Abstrak: Nowadays consumer preference in consuming food is not only about nutrition value but also good shape, taste, and mouthfeel. Tofu is nutritious food that belongs to curd-basis food. Tofu needs good shape, taste, and mouthfeel so it can be accepted by consumer. One of the tofu mouthfeel parameter is texture. Curd/tofu texture is influenced by soybean quality, coagulant type, coagulation process, and curd protein composition. Whey or tofu whey, one of the acid coagulant types, is usually used by tofu industries in Indonesia. The Influences of whey age and initial temperature of coagulation process to coagulated protein electrophoretic pattern and texture quality of curd have been studied by this research. There were three aged-difference whey; one, two and three-days, and two initial temperature of coagulation process; 63 oC and 83 oC, used in this research. One, two, and three-days whey have different pH value which are 3.81, 3.83, and 3.87 respectively. Different whey age causes different texture profile. Three-days whey produced curd with lowest hardness value, 1.48 kg Force at 63 oC and 1.98 kg Force at 83 oC. Hardness value has direct proportional correlation with cohesiveness, gumminess, and springiness. Two-days whey produced curd with highest hardness value, 1.74 kg Force at 63 oC and 2.66 kg Force at 83 oC. Hardness has proportional correlation with portion of glycinin, glycinin/β-conglycinin ratio and curd protein content. But hardness has inversely correlation with curd water content, portion of β-conglycinin, and curd solid content. Different coagulation temperature also causes different texture profile.
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Judul: Ornithonyssus Bursa (Berlese, 1888) Famili Macronyssidae yang Menyerang Unggas Dan Penaggulangannnya
Abstrak: Ornithonyssus bursa adalah tungau penghisap darah pada unggas di daerah tropis dan subtropis. Tungau ini relatif kecil, dengan panjang tubuh antara 700-1000 mikron dan lebarnya 250-490 mikron. Tubuhnya bulat berwarna coklat kekuningan sebelum menghisap darh dan berwarna merah setelah menghisap darah dari induk semangnya.
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