Judul: Cassava Chunk Product Stability in Retort Pouch Packaging During Storage
Abstrak: Singkong merupakan salah satu bahan pangan sumber karbohidrat utama di Indonesia. Singkong dapat diolah menjadi produk cassava chunk, yaitu potongan singkong steril komersial dalam kemasan retort pouch siap santap. Produk ini dapat berfungsi sebagai pengganti nasi, praktis, dan dapat didistribusikan lebih jauh. Penelitian sebelumnya telah dilakukan mengenai optimasi proses sterilisasi komersial produk cassava chunk pada skala presto 25 L dengan perlakuan blansir sehingga didapat nilai Fo 3,43 menit. Namun, penelitian tersebut belum menganalisis stabilitas produk. Penelitian ini bertujuan mengonfirmasi parameter proses sterilisasi komersial produk cassava chunk pada skala presto 50 L dan menggunakan kemasan aluminium foil, serta mengevaluasi stabilitas produk selama penyimpanan dengan metode Accelerated Shelf Life Testing (ASLT) pendekatan Arrhenius. Produk cassava chunk disimpan pada suhu 35, 45, dan 55 ℃ selama 35 hari dan dianalisis setiap 7 hari sekali. Parameter yang dianalisis adalah warna, tekstur, pH, serta sensori dengan atribut warna, aroma woody, keasaman, dan kepahitan. Parameter nilai L, aroma woody, dan keasaman memiliki perubahan yang lebih signifikan dibandingkan dengan parameter lainnya. Atribut keasaman merupakan parameter kritis yang digunakan untuk menentukan umur simpan karena paling berpengaruh terhadap penerimaan konsumen dan memiliki umur simpan yang lebih pendek. Pendugaan umur simpan produk cassava chunk adalah 1,3–1,5 bulan pada selang suhu penyimpanan 25–30 ℃ dan 2,8 bulan pada suhu refrigerasi., Cassava is one of the main carbohydrate sources in Indonesia. Cassava can be processed into cassava chunk products, namely commercially sterile cassava pieces in ready-to-eat retort pouches. This product can serve as a substitute for rice, is practical, and can be distributed further. Previous research has been conducted regarding the optimization of the commercial sterilization process for cassava chunk products on a pressure scale of 25 L with blanching treatment so that the Fo value is 3.43 minutes. However, these studies have not analyzed the stability of the product. This study aims to confirm the parameters of the commercial sterilization process for cassava chunk products at a pressure scale of 50 L and using aluminum foil packaging, and evaluate the stability of the product during storage using the Accelerated Shelf Life Testing (ASLT) method with the Arrhenius approach. The cassava chunk product was stored at 35, 45, and 55 ℃ for 35 days and analyzed every 7 days. Parameters analyzed were color, texture, pH, and sensory attributes with color, aroma, acidity, and bitterness. Parameters of L value, aroma, and acidity had more significant changes compared to other parameters. The acidity attribute is a critical parameter used to determine shelf life because it has the most influence on consumer acceptance and has a shorter shelf life. The estimated shelf life of cassava chunk products was 1.3–1.5 months in a storage temperature range of 25–30 ℃ and 2.8 months at refrigeration temperature.
Keyword: Arrhenius, ASLT, cassava chunk, Fo, retort pouch

Judul: Karakterisasi dan Analisis Kluster Tepung Singkong Terfermentasi Varietas Indonesia
Abstrak: Indonesia has various types of cassava with different physicochemical characteristics. Cassava can be processed into fermented cassava flour (FCF), which is an intermediate cassava-based product used as a raw material in food industries. To enhance the database of cassava varieties in Indonesia, this study aimed to characterize the chemical composition and pasting profiles of FCF produced from 28 different Indonesian cassava varieties. The FCF samples were analyzed in terms of chemical composition (moisture, ash, protein, fat, carbohydrate, starch, amylose, amylopectin, and cyanide content) and their pasting properties (peak viscosity, hot paste viscosity, breakdown viscosity, final viscosity, setback viscosity, pasting temperature, peak time, and gel strength). The chemical composition data were subsequently analyzed using Principal Component Analysis (PCA) and Agglomerative Hierarchical Clustering (AHC). This research discovered that the 28 cassava varieties had a significant effect on moisture, ash, protein, fat, carbohydrate, starch, amylose, amylopectin, cyanide content, and gel strength (p<0.05). The highest productivity value of cassava was in UK 1. However, when combined with the FCF yield, the most efficient variety for FCF production was Barokah. The most potential cassava variety in FCF production had high cyanide and ash content that exceeded SNI. Thus, further decreasing method is needed. A decrease in ash content is needed for UK1, Darul Hidayah, Manggu Bogor, and Kubar B, while a decrease in cyanide content is needed for Barokah, Gajah B, Randu, and Genjah Bayam. Some varieties were potential for tapioca raw material, namely UK 1, Barokah, and Malang 4. The result of pasting properties showed a relatively wide range of each parameter, indicating a potential wide range of food application. The PCA of chemical composition visualized the relationships and similarities among the different cassava varieties based on their ash, starch, amylose, amylopectin, and cyanide content. Based on the same factors, three clusters of FCF were identified: the first cluster had the lowest level of ash, starch, and amylopectin content but has the highest amylose and cyanide content; the second cluster displayed demonstrated the highest ash content and the lowest cyanide content, and the last cluster exhibited the highest levels of starch, amylopectin, but intermediate ash, amylose, and cyanide content. These findings successfully identified cassava varieties with a potential application as a food ingredient., Indonesia memiliki berbagai jenis singkong dengan karakteristik fisikokimia yang berbeda-beda. Singkong dapat diolah menjadi tepung singkong terfermentasi atau fermented cassava flour (FCF) yang merupakan produk antara untuk bahan baku industri makanan. Untuk meningkatkan data varietas singkong di Indonesia, penelitian ini mengkarakterisasi komposisi kimia dan sifat pasta pada FCF yang dihasilkan dari 28 varietas singkong berbeda yang ada di Indonesia. Sampel FCF dianalisis kandungan kimianya (kadar air, abu, protein, lemak, karbohidrat, pati, amilosa, amilopektin, dan sianida) dan sifat pasta (viskositas puncak, viskositas jatuh, viskositas pasta panas, viskositas akhir, viskositas balik, suhu pasting, waktu puncak, dan kekuatan gel). Data komposisi kimia selanjutnya dianalisis menggunakan Principal Component Analysis (PCA) dan Agglomerative Hierarchical Clustering (AHC). Penelitian ini memperlihatkan bahwa 28 varietas ubi kayu berpengaruh signifikan terhadap kadar air, abu, protein, lemak, karbohidrat, pati, amilosa, amilopektin, sianida, dan kekuatan gel (p<0,05). Nilai produktivitas umbi singkong tertinggi ada di
Keyword: cassava, characterization, cluster, fermented, flour

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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