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: Pendugaan Umur Simpan Permen Jelly Pepaya (Carica papaya L).
Abstrak: Papaya (Carica papaya L) is a kind of fruits which is concluded in Caricaceae family. This fruit is a yearly fruit so it exists for a whole year. It is needed to make some efforts in order to utilize papaya, then it will increase the economic value of papaya. One of them is by making processed product from papaya, for example papaya jelly candy. The general aim of this research was to produce papaya jelly candy. The special aim of this research was to know the quality changing during storage, also predict shelf-life of the product, and to know the best packaging for the product of papaya jelly candy. Shelf life is time that is needed for a product in a certain storage condition to get into a certain level of quality. Shelf life is determinated by using accelerated storage studies (ASS) method. It was done by using such condition that could accelerate the degradation process of quality of the product. The packaging and storage condition is assumed could lengthen product’s shelf life and suppress degradation rate of papaya jelly candy. In this research, papaya jelly candy was packed in three different packaging. Those were polypropylene (PP) plastic, aluminum foil and glass packaging. Storage was held at 5, 15, 25, and 35˚C. This research consists of three stages. Firsting, the material preparation and making of papaya jelly candy. Second, packing and storage papaya jelly candy in different packaging and storage temperature. Third, analysis quality product. Material characterized before treatment, with proximate and microbial analysis. Proximate analysis consisted of water, ash, protein, fat, high fiber content, carbohydrate, pH, and aw. Microbial analysis included mold analysis of papaya jelly candy. Besides that, there was another analysis to know material characterization during storage. Those are water content, total titrated acid, vitamin C content, texture, color analysis, and sensory evaluation test. Based on the research result, it was known that quality of papaya jelly candy was changing during storage. Water content of papaya jelly candy was increasing in every packaging and at every temperature of storage. Water content increased in PP plastic packaging at 5, 15, 25, and 35°C, were 0,11, 0,13, 0,16, and 0,17% respectively per day. Water content increasing of papaya jelly candy in aluminum foil packaging at 5, 15, 25, and 35°C were 0,08, 0,10, 0,13, and 0,14% per day. While water content increasing of papaya jelly candy in glass packaging the same temperature were 0,12, 0,15, 0,15 and 0,19% per day. Vitamin C content and Total Titrated Acid of papaya jelly candy decreased 0,01% per day in all of packaging and all storage temperature.
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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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