Judul: The improvement of cooked shrimp’s surimi based edible coating from red snapper fillet waste (Lutjanus sp.)
Abstrak: Cooked shrimp is a value added product with high protein content, specific taste, ready to eat, and have an interested colour for consumers. Cooked shrimp must be protected from quality deterioration during storage. The purpose of this study was to determined physical characteristics of edible coating made from meat of red snapper fillet waste; examined the effectivity of surimi edible coating protection towards physic, chemistry and microbiology damage indicators; learned surimi edible coating application to inhibit the quality deterioration of cooked shrimp during storage at 1-5 oC. Surimi concentration that used as edible coating were 2, 6, 10, and 14% (w/v), each edible coating treated with two treatments, which were without and added by secang extract. Peeled undevined (PUD) vannamei (Litopenaeus vannamei) with size 60-70 was used as object. Application of surimi edible coating on cooked shrimp was comprised boiled then coated and coated then boiled. Quality of cooked shrimp alteration was determined everyday, including total plate count (TPC), total volatile base (TVB), pH, water content, aw, water holding capacity (WHC), and colour exchange. The treatments giving best result were edible coating with 14% surimi concentration, added by secang extract, and processed with boiling then coating. Surimi edible coating combined with secang extract effectively protect cooked shrimp towards physic, chemistry, and microbiology damage, improved cooked shrimp appearance, stabilized colour during storage, and extended the shelf life until 6 days.
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Judul: Application of Edible Coating Bases Extract of Lindur (Bruguiera gymnorrhiza) and Chitosan on Peeled Off Shrimp
Abstrak: Peeled off shrimp is usually sold at supermarkets and displayed at an air conditioned equipped with lights. This condition causes the temperature of display room increase more than 10 °C from its initial temperature (-1.6 °C), therefore the products presented will suffer a quality degradation. Edible coating can be applied as a packaging to protect shrimps from any damage during storage, to extend the storage period and maintain products’ quality. Besides chitosan, the extract of fruit of lindur plant (that belongs to mangrove group) is suggested as have preservative and antimicrobial activities. In the present study, edible coating was formulated using a combination of chitosan (0 %, 1 %, 2 %) and lindur fruit extract (0 %, 1 %, 2 %). The study was conducted in two phases, there are introduction phase ( includes chemical analysis of fruit and flour lindur , characterization of chitosan (degree of deacetylation), making lindur flour, making of lindur extract, and analysis of antimicrobial activity. Primary Research Series using Black Tiger shrimp (includes TVB analysis, pH, TPC and hedonic sensory (color, aroma, texture and over-all) at 1 day and 7 days storage. Secondary Research Series using vannamei shrimp (includes TVB analysis, pH, TPC, Organoleptic Quality (texture, appearance and aroma of cooked and raw shrimp and flavor of cooked shrimp), Texture by Texture Profile Analyzer, and color analysis at 1 day , 4 days and 7 days storage . In experiments with the Black Tiger shrimp, edible coating from extracts lindur 1 % without chitosan (K0L1) and extract lindur 2 % without chitosan (K0L2 ) capable significantly lowering the pH value, TPC, and TVB compared with controls. Meanwhile, in experiments with shrimp Vannamei, edible coating from extracts lindur 2 % without chitosan (K0L2) capable of significantly lowering the pH value , TPC, and TVB peeled shrimp compared to controls on the storage 10 °C for 7 days. Physical parameters of color, texture and organoleptic characteristics of appearance, odor, texture, flavor and hedonic parameters also significantly different to the control parameters. The combination of chitosan and extracts lindur proved less than optimal in maintaining the microbiological parameters, physical parameters, and organoleptic parameters on peeled shrimp. I,oThis study demonstrated that lindur’s extract can be an alternative as antibacterial materials and it is effective as a natural preservative for peeled shrimp.
Keyword: edible coatings, lindur (Bruguiera gymnorrhiza), chitosan, peeled off shrimp

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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