Judul: Proses Pengolahan Selai Nanas Organik dan Pendugaan Umur Simpannya
Abstrak: Tapos pineapple is a specific kind of pineapple from Bogor, West Java. Tapos pineapple is called Gati pineapple in its former area. The uniqueness of this pineapple from Tapos is that this pineapple is planted naturally, without any addition of chemical fertilizer and pesticides, and that is why it is also called ‘organic’ pineapple. During harvest time, Gati pineapple had an excessive availability and it is sold in the ‘fresh fruit’ form so that its price is so low or its price is the same as nonorganic pineapple. This condition will disadvantage the farmers. One of the alternatives to raise pineapple’s price is converting pineapple into product that has an added value, such as pineapple jam. Organic pineapple jam could be made without chemical addition, but it was used natural materials, such as sugar, orange extract, jelly, clove, cinnamon and salt. The aim of this research is to get the processing technology of organic pineapple jam, characteristic product pineapple jam and shelf-life estimation in glass jar and polypropylene plastic packaging. Organic pineapple jam in glass jar and polypropylene packaging then was kept at 250C, 350C and 450C. Shelf-life estimation in polypropylene plastic and glass jar was using Arrhenius acceleration method. Parameters that were checked during storage were water content, total acid, pH and colour. The processing of pineapple jam consisted of materials preparation, cooking, packaging sterilization, packaging, pasteurization and cooling. Then each of packedpineapple jam was kept in incubator. During storage there was quality changing from pineapple jam. It was seen from water content analysis. Pineapple jam in polypropylene plastic packaging had increased-water content right after storage (based on first week analysis), then its water content was decreased or remained stable at 26 - 32%. Pineapple jam in glass jar packaging also had increased-water content right after storage (based on first week analysis), then its water content was decreased or remained stable at 26 - 35%. Total acid of pineapple jam in glass jar packaging was increased during the first week of storage, while total acid of pineapple jam in polypropylene plastic packaging was decreased during the first week of storage and then both of them remained constant at 0.9 - 1.1 g/100 g. Usage of polypropylene plastic and glass jar as pineapple jam’s packaging materials did not affect changing of pH value during the first week of storage. Both of these materials were slightly decreased or remained stable at 3.38 - 3.67. Color or brightness value of organic pineapple jam were relatively decreasing in all of packaging materials and all of storage temperature’s range during storing period. The highest temperature during storage, then the decreasing rate of brightness value of pineapple jam would be higher. Jam is a fruit based product that has semi paste or semi wet form. Critical parameter for semi wet food product is water content. It explained that amongst the critical parameters that have been used (water content, total acid, pH and color), water content showed a significant difference during storage with critical point of 35%. Shelf life of organic pineapple jam in glass jar packaging was
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Judul: Kajian Teknik Pengemasan Buah Pepaya Dan Semangka Terolah Minimal Selama Penyimpanan Dingin
Abstrak: Papaya and Watermelon are one of the famous agriculture commodity. As a agriculture products, they are perishables. This is because papaya and watermelon are still doing metabolitic activity (respiration). The effect of papaya and watermelon respiration is chemical changing so that caused physical changing. The physical changing as a result of chemical changing could be perceived directly as a color, aroma, texture and flavour changing. People generally prefer to consumed them in cold condition. Before they are ready to consume, papaya and watermelon are processed minimally, including fruits cleaning, paring, and cutting into a smaller size so that make them more interesting and easier to consume. They also has a big size so they havenot finished consumed in once time. So, usually people cut them several time during consumption. Minimally processed cause injury in the fruits so that make it shorter in storage life. The way that we can do to prolong the storage life of the minimally processed of papaya and watermelon is a proper packaging and cold storage. The aim of the research is to get characteristic of packaging, physical, chemical, microbiology’s characteristic of fruits, and quality parameter changing and organoleptic assesment for cold storage according to the technique packaging. It also determine the suitable packaging for the fruits during cold storage. Storage were conducted at five treatment that is using polypropylene packaging with two opened circulation holes (B1), polypropylene packaging with one opened circulation hole (B2), polypropylene packaging with two closed circulation holes (B3), plate with cling film plastic cover (B4), plate with no cover (B5) and conducted in the chiller refrigator with 5 - 100C temperature. The parameter which were tested are proximate test (including water content, ash content, protein content, faty content and fiber content) and quality analysis including physical parameter (texture and color), chemical parameter (water content, total acid content, pH, total sugar content, Aw, vitamin C), microbiological test (TPC) and organoleptic test. The parameter were tested during 14 days storage. The result of research showed that thickness, gramature and density of polypropylene packaging is higher and transmission rate (O2, CO2, H2O) is lower than cling film plastic packaging. Characteristic of papaya and watermelon showed that both of them had a relatively high water content (> 80%), watermelon’s texture was lower than papaya’s, neutral’s pH (6.10 for papaya and 5.60 for watermelon), papaya and watermelon’s Aw were 0.82 dan 0.80. They also has a relatively low carbohydrates, protein, and fat. The result also showed that during storage was occurred the increasing microbiological test (TPC). It cause the increasing of water content (except in B5), decreasing of total sugar content, increasing of total acid and decreasing of pH, increasing of color brightness (except in B5), and 0Hue (except in B5 of watermelon) and also increasing of texture content. Organoleptic test showed that fruits that in plate with no cover (B5) had the highest decreasing than the other. Panelists still like the fruits that packed in all of polypropylene packaging (B1, B2, B3) until nine to twelve days, fruits in plate with cling film cover (B4) until eight
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Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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