[abstrak] REKAYASA MEDIUM FERMENTASI UNTUK PRODUKSI L-LISIN OLEH Corynebacterium glutamicum ATCC 21513 DENGAN MENGGUNAKAN MOLASSES SEBAGAI SUMBER KARBON (FERMENTATION MEDIUM MODIFIED TO PRODUCE L-LYSINE BY Corynebacterium glutamicum ATCC 21513 USING MOLASSES AS SOURCE OF CARBON)

By: Dasarani DD, Rahayu WP , Satiawihardja B

Department of Food Science and Technology, Bogor Agricultural University

Corynebacterium glutamicum ATCC 21513 is one of mutant strains that is made for producing a large amount of L-lysine. This strain has homoserine auxotroph character (double auxotroph i.e. menthionin and threonin), leucine auxotroph, and penicillin resistance. In mutant auxotroph, L-lysine production will increase if essential nutrients are included into their fermentation media. In this study, an effort was made to increase L-lysine production by adding certain amount of methionine, threonin, and leucine, which was intended to enrich such amino acids contained in pepton, into a medium. For changing cell wall permeability, penicillin was added into fermentation media to release L-lysine from the cells and resulted in L-lysine accumulation.

Keywords:fermentation, L-lysine, Corynebacterium glutamicum, molasses

Dimuat pada Jurnal Agroland, Volume 8 No.1, 2001, ISSN 0854-641X

[abstrak] SEPARASI KOMPONEN FLAVOR YANG DIPRODUKSI OLEH Hansenula anomala DENGAN MENGGUNAKAN KOLOM KROMATOGRAFI (SEPARATION OF FLAVOR COMPOUNDS PRODUCED BY Hansenula anomala USING COLUMN CHROMATOGRAPHY)

By: Rahayu WP, Apriyantono A, Kusumaningrum J

Department of Food Science and Technology, Bogor Agricultural University

Column chromatography can be used to separate flavor compounds from mixture solution. With this method, food grade solvent can be used, so the result can be applied for foods. To separate flavor compounds present in fermentation solution produced by Hansenula anomala, silica gel was the adsorbent of choice for separation using column chromatography. The result showed that percentage of component which can be eluted from silica gel column was higher than active carbon or C18 column. Using silica gel column, compounds such ethyl acetate, isoamyl acetate, and isoamyl alcohol, can be eluted at amount of 87.0, 74.8 and 89.5%, respectively. Separation using silica gel column with 100 ml fermentation solution is more efficient than 10 ml fermentation solution. The result showed that percentage of component eluted from the first column with 100 ml sample is 21.1, 66.2 and 85.5% for ethyl acetate, isoamyl acetate and isoamyl alcohol, respectively.

Keywords: flavor, fermentation, Hansenula anomala, column chromatography

Dimuat di Jurnal Ilmu dan Teknologi Pangan, Volume 3 No. 1, 1998, ISSN 1410-0142

[abstrak] OPTIMASI PENGGUNAAN ASAM AMINO SEBAGAI PREKUSOR PADA PRODUKSI KOMPONEN FLAVOR KAMIR Hansenula anomala (OPTIMIZATION OF AMINO ACID USED AS PRECURSOR IN FLAVOR PRODUCTION BY THE YEAST Hansenula anomala)

By: Rahayu WP, Susilo P, Jenie BSL, Wijaya CH, Apriyantono A

Department of Food Science and Technology, Bogor Agricultural University

The aims of this study were to determine the best amino acid which function as flavor precursor; the concentrations of the amino acid and fermentation time to give the optimum result. As compared to isoleucine and valine, leucine gave the best result at shown by the highest flavor (banana and frambozen-aroma) produced by Hansenula anomala in coconut–water medium. This amino acid also produced the highest amount of ester. In the medium containing leucin, optimization of leucine concentrations and fermentation showed that within 6 days of fermentation, leucine at 1.0% gave the best result. Analysis using GC-MS showed that among all volatiles produced within 6 days of fermentation in the presence of leucine, certain volatile compounds were directly related to banana-like flavor. These volatile compounds were isoamyl acetate, pentyl acetate, isoamyl alcohol and pentyl alcohol. Together with isobutyl alcohol, acetic acid, 2-methylpropanoic acid and 3-methylbutanoic acid, these volatiles can also form a raspberry–like flavor.

Keywords: flavor, amino acid, fermentation, Hansenula anomala

Dimuat di Buletin Teknologi dan Industri Pangan, Volume 9 No. 2, 1998, ISSN 0216-2318

 

[abstrak] PEMBUATAN CIDER JAHE (Zingiber officinale Roscoe) (CIDER FROM GINGER (Zingiber officinale Roscoe))

By: Rahayu WP, Rusiana I

Department of Food Science and Technology, Bogor Agricultural University

The fermentation of ginger with Saccharomyces cerevisiae to develop a new cider type product had been studied. The result showed that starter of dried baker’s yeast produced cider with larger amount of alcohol and acid than that made with pure culture. The more sugar added to ginger solution and the longer period of aging increased pH value, alcohol, and ester content. However increasing period of aging decreased the amount of sugar and total acid. Prolonged aging period also reduced the clarity of cider made with higher sugar concentration. Sensory evaluation results showed that the best ginger cider obtained was made with yeast, 15% sugar and 0 or 10 days of aging.

Keywords: ginger, fermentation, cider

Dimuat di Buletin Teknologi dan Industri Pangan, Volume 9 No. 1, 1998, ISSN 0216-2318

 

[abstrak] PERUBAHAN MUTU PIKEL JAHE (Zingiber officinale Roscoe) SELAMA PENYIMPANAN (THE QUALITY CHANGES OF GINGER (Zingiber officinale Roscoe) PICKLE DURING STORAGE)

By: Rahayu WP, Wibowotomo B

Department of Food Science and Technology, Bogor Agricultural University

The aim of this study was to observe the quality changes of pickle made from salt-stock ginger during storage. The result showed that the best product was pickle made from stick ginger, fermented with 10% salt solution with 2% sugar and packed in jars at low temperature (5-10oC). The time of storage until 3 month was the best. During storage, the value of pH was relatively constant, total acid increased but the total volatile acid decreased. Pickle packed in jars and stored at low temperature (5-10oC) appeared more clearly than pickle in plastic bag stored at room temperature (25-30oC). This observation might be well related to the lower soluble solid found in the first treatment, although the clearness decreased during storage. Pickle packed in plastic bag and store at low temperature was easily damage by yeast and mold but their organoleptic characters were better.

Keywords: ginger, fermentation, pickle

Dimuat di Buletin Teknologi dan Industri Pangan, Volume 9 No. 1, 1998, ISSN 0216-2318

 

[abstrak] PRODUKSI SENYAWA AROMA OLEH BEBERAPA JENIS FUNGI DALAM MEDIA LIMBAH PENGOLAHAN BUAH-BUAHAN (FLAVOR COMPOUNDS PRODUCTION BY SEVERAL FUNGI USING FRUIT WASTE PRODUCTS MEDIA)

By: Jenie BSL, Faridah, Rahayu WP, Apriyantono A, Widjaya CH

Department of Food Science and Technology, Bogor Agricultural University

Five species of fungi i.e. Candida utilis, Hansenula anomala, Neurospora sitophila, Penicillium sp. and Trichoderma viride were used to produce aroma compounds in four kind of media containing fruit waste products (coconut water, pineapple peel and core, orange peel, and nutmeg fruit). Sensory evaluation test and measurement of ester content of the fermentation broth revealed that H. anomala produced the best aroma. Optimization studies found that the intensity of the aroma could be improved by adjusting the sugar content in the media to 3 oBrix, adding 0.1% leucine as the nitrogen source, and 0.53% acetic acid as well as 0.77% isoamyl alcohol as the precursors. Other optimum conditions were the initial pH 5.0, agitation at 150 rpm and 6 day fermentation time. The description of the aroma compounds produced by H. anomala were raspberry, banana, ethereal, and alcoholic. The aroma compounds analyzed by gas chromatography consisted of mairly isoamyl acetate, ethyl acetate, and ethyl laurate.

Keywords: flavor, fermentation, fungi, H. anomala

Dimuat di Jurnal Ilmu dan Teknologi Pangan, Volume 1 No.2, 1996, ISSN 1410-0142

 

[abstrak] PEMBUATAN PIKEL JAHE (Zingiber officinale ROSCOE) (SALT-STOCK PICKLE FROM GINGER (Zingiber officinale ROSCOE))

By: Rahayu WP, Wibowotomo B

Department of Food Science and Technology, Bogor Agricultural University

Young ginger is popular as a delicacy product; however, it damages easily due to poor storage. Pickling is an alternative process to prolong its self life. This study showed that the best salt-stock ginger pickles were obtained from fermentation of (1) sliced ginger with 10% salt solution with additional salt powder added in layers as much as 1:10 (w/w) (formula 1) and (2) ginger stick with 10% salt solution and 2% sugar (formula 2). Pickle made from formula 2 had low pH value, high total acid, and high score in color, texture and overall acceptance. This pickle also had higher scores in odor and taste.

Keywords: ginger, fermentation, pickles

Dimuat di Buletin Teknologi dan Industri Pangan, Volume 7 No.1, 1996, ISSN 0216-2318

 

[abstrak] ISOLASI DAN IDENTIFIKASI MIKROORGANISME PENGHASIL FLAVOR DARI BEBERAPA JENIS BUAH (ISOLATION AND IDENTIFICATION OF FLAVOR PRODUCING MICROORGANISMS FROM SEVERAL TROPICAL FRUITS)

By: Rahayu WP, Saparianti E, Jenie BSL, Apriyantono A, Widjaya CH

Department of Food Science and Technology, Bogor Agricultural University

The research was conducted to select microorganisms capable of producing flavor components in high amount and reminiscent to the odor of fruits. The mould and yeast were isolated from tropical fruits like citrus, pineapple and nutmeg. The isolates obtained were 3 mould isolates from nutmeg, 3 yeast isolates from citrus and 3 yeast isolates from pineapple. Only one isolate from pineapple (N2 isolate) suggested as Candida sp. produced a pleasant aroma. This yeast was the grown in the medium containing coconut water adjusted to 6 oBrix of total soluble solids and pH 4.5. After 9 days of fermentation, the strawberry aroma was produced and the average panelist gave similar score to the fermentation product.

Keywords: flavor, citrus, pineapple, nutmeg, Candida sp., fermentation

Dimuat di Buletin Teknologi dan Industri Pangan Volume 6 No. 1, 1995, ISSN 0216-2318

[abstrak] ANALISIS KOMPONEN FLAVOR YANG DIHASILKAN OLEH Hansenula anomala YANG DITUMBUHKAN PADA SUBSTRAT AIR KELAPA (ANALYSIS OF FLAVOR COMPONENTS PRODUCED BY Hansenula anomala GROWN ON COCONUT WATER SUBSTRATE)

By: Wijaya CH, Kusumaningrum H, Rahayu WP, Amahorseya V

Department of Food Science and Technology, Bogor Agricultural University

Many studies on microbial flavor were directed to find new source of natural flavor. Hansenula anomala is a yeast film, produces little alcohols but is able to produce esters, especially ethyl acetate. The aim of this research was to examine the effects of fermentation (pH) and extraction methods on flavor components from H. anomala grown on coconut water substrate. Five major components were observed, three of them were identified as ethyl acetate, isoamyl acetate, and ethyl laurate. These five components are extracted from the cell. It was found that production of each component was affected by pH of the substrate. Flavor compounds obtained were affected by the extraction methods.

Keywords: flavor, Hansenula anomala, fermentation, ethyl acetate

Dimuat di Buletin Teknologi dan Industri Pangan Volume 6 No. 1, 1995, ISSN 0216-2318

 

[abstrak] PEMBUATAN KEFIR-BIJI KECIPIR (Psophocarpus tetragonolobus) SERTA PERUBAHAN MUTUNYA SELAMA PENYIMPANAN (KEFIR FROM WING BEAN AND THE QUALITY CHANGES DURING STORAGE)

by: Halim D, Rahayu WP, Suliantari

Department of Food Science and Technology, Bogor Agricultural University

Wing bean is one of the protein sources easily available in Indonesia. Although the protein content is high and the quality is excellent, the bean is not widely used yet. In this study, the bean is used in kefir processing to increase its economic value. The result of our experiment showed that addition of 4, 6, and 8% skim milk and 6% sugar upon the wing bean milk produced kefir with good sensory quality. Addition of the skim milk increased the total acid, total volatile acid, alcohol content of the fermented kefir. Incubation at room temperature produced kefir with lower alcohol content and pH values compared with those incubation at 22oC. The kefir stored at 4oC was not easily deteriorated as those stored at room temperature.

Keywords: wing bean, fermentation, kefir,

Dimuat di Buletin Ilmu dan Teknologi Pangan, Volume 1 No. 2, 1990