Indian Journal of Biotechnology Vol 8, July 2009, pp 304-310

Influence of Pediococcus acidilactici as a starter on the flavour of tempoyak (fermented )

Neti Yuliana 1* and Virgilio V Garcia 2 1Jurusan Teknologi Hasil Pertanian (THP), Fakultas Pertanian, Universitas (UNILA). Jalan Sumantri Brojonegoro #1 Bandar Lampung, 2 Institute of Food Science and Technology, University of the Philippine at Los Banos, Philippines Received 24 July 2008; revised 28 November 2008; accepted 10 February 2009

Pediococcus acidilactici UP02 was used as a starter for the fermentation of tempoyak ( Durio zibethinus Murr.), a traditional Indonesian fermented fruit. The flavour of tempoyak was compared to those in spontaneous fermentation (no starter added). The results showed that addition of P. acidilactici UP02 in tempoyak fermentation decreased the quantity of sulphur components, reduced the sugar content, and increased various non-sulphur compounds as well as, non-volatile acidity and contents of organic acids (lactic, malic, and acetic). Sensory evaluation showed that there was no significant difference among the samples for sourness and aroma. However, the P. acidilactici UP02-inoculated sample was more acceptable than the sample with no-starter treatment. On the basis of the results of GC-MS, the flavour components of tempoyak with P. acidilactici UP02 treatment were observed to have 48 compounds, mainly composed of dimethyl disulfide and diethyl disulfide followed by ethane,1-1-bis ethylthio.

Keywords: Pediococcus acidilactici , tempoyak, malic acid, sulphur components

Introduction final pH of 3.8 to 4.6 whereas, the acidity content of Tempoyak ( Durio zibethinus Murr.) is a fermented tempoyak from Indonesia is 2.55 and 2.56% (as lactic durian, which is a popular and in acid) 6-8. This high acidity of tempoyak is attributed to and Indonesia, mainly in and lactic acid bacteria (LAB) 4,9,10 . Several researchers islands 1,2 . This product is creamy, yellow- have isolated many species of LAB from tempoyak. white in colour, and has a distinctive aroma. It is Lactobacillus plantarum, L. brevis, L. mali and L. prepared by placing durian pulp in jars to which salt fermentum have been found in Malaysian (2-15%) is added and carefully mixed. The jars are tempoyak 10,11 , whereas L. plantarum, L. casei and L. then tightly closed and kept for 7 d to let spontaneous corynebacterium have been found in tempoyak from fermentation to take place 3,4 . During fermentation, the Indonesia 12 . A new species, Lactobacillus durianis , texture of the durian pulp changes from solid to a isolated from Malaysian tempoyak, has also been semisolid mass accompanied by a strong flavour; the reported 13 . Other LAB found in tempoyak are flavour is the result of a unique combination of Leuconostoc mesenteroides 12 , Pediococcus various sugars, organic acids as well as various acidilactici and Weissella mesenteroides 4. Historically volatile organic compounds. The volatile organic the species of Lactobacillus, Leuconostoc, compounds in tempoyak consist of sulphur-containing Pediococcus, and Streptococcus are the main species compounds; 3,5-dimethyl-1,2,4 trithiolane being the of LAB. highest, and non-sulphur compounds with butanoic There are numerous examples of controlled acid, 2-methyl ethyl ester being the highest 4. Three fermentation using LAB as a starter for the processing organic acids include acetic, lactic and malic; malic of foods, such as, green olive, fermented soymilk, and being the most abundant 5. These organic acids not minced mackerel production 14-16. The use of a starter only contribute to taste compounds, but also increase culture provides consistency and reliability of the acidity of tempoyak. The acidity of tempoyak performance. Reports on the LAB as starters for produced in Malaysia is 3.6% (as acetic acid) with a tempoyak are limited. Fermentation, using starters, may affect the flavour of tempoyak. LAB can vary ______*Fax: 62-0721-781498 metabolite reactions that produce various 17-19 E-mail: [email protected] compounds . These compounds are important as YULIANA & GARCIA: INFLUENCE OF P. ACIDILACTICI ON FLAVOUR OF TEMPOYAK 305

they impart characteristic taste and aroma to the final Evaluation of Individual Organic Acids product. The objective of this research was to evaluate A 20 µL of tempoyak sample was injected after the flavour in tempoyak using P. acidilactici UP02 as filtering through a 0.45 µm membrane filter in a a starter, which has homofermentative nature and its Seppack C-18 cartridge (Waters Associate, USA). origin from tempoyak has been reported in a previous HPLC conditions were as follows: Merck Polysphere study. OA HY column (6 mm × 300 mm); mobile phase 0.01 N H 2SO 4; flow rate 0.8 mL/min. The peak areas of Materials and Methods each organic acid in the samples were calculated from Preparation of Inoculum the integrator system of the HPLC data station. Pediococcus acidilactici UP02 was obtained from Organic acid standards used were lactic, malic, acetic, the Institute of Food Science and Technology, succinic and citric. University of the Philippines, Los Banos, Philippines. This isolate was cultured and sub-cultured Determination of Total Volatile Acid Content anaerobically in the MRS medium (Difco, USA). The To an approximately 10 g homogenized sample cultures were centrifuged for 15 min at 3000 rpm and contained in a distilling flask, 100 mL of distilled resuspended in saline solution (0.85% NaCl) to yield water was added. Distillation was conducted rapidly 10 8CFU/mL for a working starter. until 100 mL of distillate was collected. The distillate was titrated when still hot with standard 0.1 N NaOH, Preparation of Tempoyak using phenolphthalein as an indicator. The results The flesh of the was aseptically taken and have been expressed as mg malic acid/g sample (wet divided into two sets of four representative treatments basis). comprising both with and without starter, and the Determination of Total Non-volatile Acid Content number of fermentation days (0,4,8 and 12). Two A 25 mL of sample (15 g diluted to 150 mL) was replications were maintained in this experiment. Salt evaporated to dryness in an evaporating dish on a was added to each treatment at the rate of 3% (w/w), steam bath and dried for 30 min in an oven at 100 oC. based on the durian flesh weight, and each lot (200 g) The residue was dissolved in 25 mL of distilled water was packed in a plastic container. One lot was and titrated with 0.1N NaOH using phenolphthalein inoculated with P. acidilactici UP02 and the other lot as an indicator. The amount of non-volatile acids was was naturally fermented (without adding starter). The calculated in terms of mL malic acid/g sample (wet inoculation rate was 1%, based on the weight of basis). durian. The samples were then kept in a cabinet at room temperature (27±1 oC) for evaluation. Samples Evaluation of Volatile Flavour Compounds from each treatment were withdrawn at 0, 4, 8, and 12 A 75 g of sample was put into an Erlenmeyer flask, d fermentation for the analysis of total volatile acids, sealed with aluminum foil with a protective seal, and non-volatile acids and reducing sugars. Data were fitted with an solid phase microextraction (SPME) gas calculated as mean of two replications. tight syringe in such a way that the syringe would be just above the food sample. The flask was placed in a o Analysis of Tempoyak water bath at 50 C with the syringe still fitted. The Procedures described by AOAC 20 were used for the volatiles released from the sample during 30 min examination of total volatile and non-volatile acids, period at 50 oC were swept onto the SPME. These were whereas reducing sugars were determined by Nelson- then analyzed using an HP 5890A gas chromatograph Samogyi method 21 . Evaluation of flavour compounds connected to an HP 5970 mass spectrometer (Hewlett- was done using the solid phase micro extraction Packard). Gas chromatography-mass spectrometry (SPME) trapping method and the quantification of (GC-MS) was operated at 70 eV in the electron impact individual organic acids by HPLC 22 as well as sensory (EI) mode over the range 35-450 amu; column used analysis was done on the 8 d fermented samples. To was SPB-5; 30 m ×0.25 mm, film thickness = 0.25 µm, assess the development of flavour during tempoyak (Supelco, Sigma-Aldrich Co.). The carrier gas was fermentation, sensory evaluation on the aroma and helium at a flow rate of 1 mL/min. The collected sourness was performed by scoring test, although volatiles were thermally desorbed at 250 oC for 2 min those on the general acceptability were performed by after desorption. The oven was heated rapidly to 60oC the hedonic test. and maintained at this temperature for 2 min before the 306 INDIAN J BIOTECHNOL, JULY 2009

temperature was increased at 10 oC min -1 to 220 oC (10 as homofermentative 24 . However, the result of this min). The constituents of samples were identified by study showed that malic acid was higher than lactic matching their mass spectra with those recorded in the acid. The homofermentative LAB produced mainly computer library (NIST98 and Wiley library). lactic acid from sugar metabolism, but significant changes in product formation could occur with sugar Evaluation of Reducing Sugars Reducing sugars were determined by the Nelson- limitation and aeration. Co-metabolism of sugars and organic acids was common and often led to the Samogyi method. To 1 mL of the sample, 1 mL of a 18 freshly prepared mixture of 25 parts copper reagent A production of a different product . to 1 part copper reagent B was added. It was mixed The organic acids present in tempoyak were not and heated in a boiling water bath for 20 min and identified in the previous studies. The advantage of rapidly cooled. To each tube of the mixture, 1 mL of this finding is that lactic acid and acetic acid contents were individually investigated using HPLC that arsenomolybdate reagent was added to stabilize the 7-9 colour. The absorbance of sample at 500 nm was differed from others. Most authors reported both measured using a spectrophotometer (Spectronic 20). acids as the total acidity through titration method. The total acidity of tempoyak was expressed as acetic The value generated was compared with a standard 6,8 curve, to get the amount of reducing sugars in the (3.6%) and lactic acids (2.55-2.56%) . sample. Total Volatile and Non-volatile Acid Content

Sensory Evaluation of Flavour Developed during Tempoyak Table 1 shows that the non-volatile acidity value of Fermentation through Scoring and Hedonic Tests starter and no-starter treatments at the start of Samples of tempoyak with and without starter were fermentation was 3.55 mg malic acid/g sample. On subjected to an 18-member panel for aroma, sourness, day-4 of the fermentation, the non-volatile acidity and acceptability evaluation through scoring and values increased significantly to 9.72 and 13.27 mg hedonic tests. Panel members consisted of Indonesian malic acid/g sample for no-starter and starter students (male and female) who were familiar with treatments, respectively. This trend was also observed durian and tempoyak. Data were analyzed by for volatile acidity. ANOVA and Duncan’s Multiple Range Test at 5% The non-volatile acidity had the highest values on level of significance 23 . day-four of fermentation and was significantly different in all treatments. Samples with P. acidilactici UP02 Results and Discussion treatment had the highest values of non-volatile acidity, Organic Acid Contents followed by the no-starter treatment. After the day-4 Five organic acids (lactic, malic, acetic, succinic fermentation, the non-volatile acidity values of all the and citric) were analyzed. However, citric and succinic acids were not found in both the starter and Table 1—Organic acids identified and changes in volatile acidity non-starter treated samples of tempoyak. The most and non volatile acidity in tempoyak inoculated with and without abundant organic acid found in tempoyak with P. Pediococcus acidilactici UP02 acidilactici UP02 starter was malic acid (14.60 Organic acids Fermentation No starter With mg/mL) followed by lactic acid (4.34 mg/mL) and a (day) Pediococcus small amount of acetic acid (1.63 mg/mL). Addition Malic 14.60±0.02 18.17±0.06 of the starter, however, showed an increase in the Lactic 3.41±0.03 4.34±0.06 amount of organic acids. This finding indicated that a Acetic 1.42±0.01 1.63±0.08 species of LAB had their own particular reactions and (mg/mL sample) could vary with the conditions of fermentation. Non-volatile acid 0 3.55±0.09 3.55 ±0.09 malic (mg/g sample) Succinic and citric acids were reported as common 4 9.72±0.09 13.27±0.19 8 9.38±0.00 12.97±0.15 non-volatile acids in one of the LAB products such as 12 9.45±0.09 12.93±0.09 Korean kimchi ( Dongchimi radish ), along with malic, Volatile acid acetic 0 0.24±0.00 0.24±0.00 22 lactic and acetic acids . The conversion of sugars to (mg/g sample) 4 2.76±0.34 0.57±0.04 organic acids was influenced by the kind of LAB and 8 2.79±0.04 0.63±0.04 its ability to ferment carbohydrates. Production of 12 2.82±0.08 0.65±0.02 lactic acid was a common characteristic in Values are expressed as mean ± standard deviation of two homofermentatives 3 and P. acidilactici was grouped determinations YULIANA & GARCIA: INFLUENCE OF P. ACIDILACTICI ON FLAVOUR OF TEMPOYAK 307

samples gradually decreased (Table 1). This was 0.33%; the highest value reached after 21 d of probably because of the initial reaction of the acids fermentation 25 . The volatile acidity in tempoyak was with alcohol in the formation of other metabolites. also probably contributed by octanoic, ethane dithioic, Volatile acid value of all the samples, as shown in hexanoic and ethylthiobutanoic acids, besides acetic Table 1, at the beginning of fermentation, was 0.24 acid, as analyzed by GC-MS 4. acetic acid/g. It was observed that the volatile acidity values of both treatments increased significantly on Volatile Flavour Compounds day-4 of fermentation (0.63-2.79 mg acetic acid/g). The analysis of an 8-d-old sample of tempoyak Samples with P. acidilactici UP02 starter had low inoculated with and without P. acidilactici UP02 for volatile acidity value (0.63 mg acetic acid/g, whereas, volatile sulphur compounds and fruity flavour the no-starter treatment had a high volatile acidity component showed that there were distinct value (2.79 mg acetic acid/g), equivalent to 0.28%. differences in the number of flavour components This value was not so different than for the volatile (Tables 2 & 3). The flavour components of tempoyak acid reported in fermented cabbage, which was around with P. acidilactici UP02 treatment were observed to have 48 compounds whereas no-starter treatment had Table 2 Sulphur components of tempoyak inculated with 22 compounds. These compounds corresponded to without P. acidilactici thiol, ester, alcohols, aldehyde, alkane, ketone, and No Components Area% small amounts of unknown substances. No With All the flavour compounds produced were Starter Pediococcus dominated by sulphur compound, diethyl tyrisulfide. 1 Disulfide,ethyl (1- * 0.38 This did not confirm with the pervious result 4, where methylprophyl)(I) 3,5-dimethyl-1, 2,4-trithiolane was reported to be 2 Methyl ethyldisulfide * 0.51 present in highest concentration in naturally 3 Unknown (S compound) 1.41 * fermented tempoyak. This difference could be 4 Disulfide,diethyl 13.44 9.8 attributed to the different variety used and maturity of 5 Ethylthio acetate * 0.33 durian as well as the different microorganism 6 Unknown (S compound) * 0.88 combinations involved. 7 1,2,4-Trithiolane, 7.02 4.39 Analysis also showed that both starter and no- 3,5-dimethyl starter treatment sample components had less ethyl 2- 8 Diethyltrisulfide 39.68 34.25 methyl butanoate, indicating that the samples had a 9 3-Ethyl,5-methyl-1,2,4-trithiolane * 0.04 less fruity flavour constituting the durian flavour. (I) Durian fruits possess two distinct odor notes, (i) a 10 2-(Methylthio) ethanol 6.5 6.82 strong sulfury -like and (ii) a delicately fruity 26 . 11 3-Ethyl,5-methyl-1,2,4-trithiolane * 0.16 It had been observed in the previous reports that ethyl (II) 2-methyl butanoate imparted the fruity durian 12 Ethyl n-prophyl disulfide 1.83 3.21 flavour 26,27 . Moreover, it has been found that this 13 3-Ethylthiobutanoic acid 0.67 * compound contributed most to the non-sulphur part of 14 Unknown (S compound) 0.52 * the durian flavour as analyzed by GC-Sniff flavour 28 15 Ethane,1-1-bis(methylthio) 1.66 1.1 dilution analysis . 16 Ethane,1-1-bis(ethylthio)(I) 13.69 7.92 The 48 volatile compounds in the sample with P. 17 Trisulfide,diprophyl * 0.26 acidilactici UP02 were characterized by the presence Disulfide,ethyl (1-methyl) prophyl of 18 sulphur, 10 ester, 2 carboxylic acid, 5 alcohol, 2 18 (II) * 0.17 aldeyhe, 2 alkane, 1 ketone, 6 unknown, and 2 N-dimethylthiophosphynil-3-amino miscellaneous compounds. Many compounds 19 pyridine * 8.5 generated in this sample were not found in 4,6-Dimethyl-1,2,3,5- the no-starter added samples, such as acetic acid; 20 tetrathiacycloghexane * 0.26 ethylthio ethane; ethylpropionate; hexanoic acid; 2,3- 21 Methanethioamide,N,N-dimethyl- * 0.5 dihydro-benzofuran; 1-acetylamino-5,5-dimethoxy- 22 3-(2-Mercapto-methyl prophyl)thio 1.65 * 2,3-dimethyl 2 pentene; germacyclobutane,1,1- * not found dimethyl; disulfide,ethyl (1 methylpriophyl); N-dim- 308 INDIAN J BIOTECHNOL, JULY 2009

Table 3—Non-sulphur components of tempoyak inoculated with ioamide,N,N-dimethyl and glycine methyl ester. The and without P. acidilactici last compound was the major constituent of the non-

No Components Area (%) sulphur volatiles present in the samples inoculated by No Starter With P. acidilactici UP02 starter. Pediococcus Among the sulphur compounds, disulfide diethyl was the second abundant sulphur compound observed 1 Acetic acid * 1.24 in all the samples with and without starter treatment. 2 Ethyl propionate * 0.21 This may be responsible for the fetid odour that was 3 Butanone, 3-hydroxyl * 0.3 noted in fermented durian. Disulfide diethyl is 4 Unknown 0.59 * reported to be responsible for the fetid odour in 5 1-Butanol, 3methyl 0.69 0.51 durian 29 . As much as 18 sulphur compounds were 6 1 -Butanol, 2-methyl- * 0.14 detected in P. acidilactici UP02 treated samples, 7 2,3-Butanediol 1.93 0.66 whereas no-starter treated showed 10 sulphur 8 1,3-Butanediol 2.14 0.75 compounds. Presence of abundant sulphur 9 Butanoic acid ethyl ester * 0.29 components caused the samples to still have a strong 10 Propanoic acid, 2-hydroxy,ethyl ester * 0.36 onion-like odour. 11 2-Butenoic acid, ethyl ester * 0.25 Head space analysis of no-starter treated samples 12 Butanoic acid, 2 methyl, ethyl revealed that 1-butanol 3-methyl; 2,3-butanediol; 1,3- ester 0.49 0.46 butanediol; butanoic acid, 2-methyl, ethyl ester; 13 Unknown * 0.16 nonanoic acid, ethyl ester; and two unknown 14 Unknown * 0.79 compounds were the principal non-sulphur aromas 15 Butanoic acid, 3-hydroxy,ethyl present. Among these existing non-sulphur ester * 0.35 compounds, 1,3-butanediol was found in highest 16 Unknown 0.46 * amount in thie samples. It was noticed that nonanoic 17 Hexanoic acid * 0.46 acid, ethyl ester, and the sulphur compound, 3- 18 Hexanoic acid, ethyl ester * 0.45 ethylthiobutanoic acid were only found in the no- 19 Unknown 0.93 0.97 starter treated samples. 20 1-Octanol * 0.34 21 Nonyl aldehide * 0.3 Reducing Sugars 22 Unknown * 0.24 The results showed that starter and no-starter 23 4-(1-Hydroxy-ethyl) gamma treatments had similar patterns of reducing sugars, butanolacton * 0.2 whose values decreased from day-0 to day-8 of 24 Ethyl octanoate/ethyl caprylate * 1.05 fermentation period (Fig. 1). This was due to the 25 2,3-Dihydro- benzofuran/acetophenon * 0.12 utilization of low molecular weight reducing sugars as 26 Nonanoic acid, ethyl ester 1.47 * a source of energy by the LAB. Higher reducing sugars content, however, was 27 Unknown 0.5 * observed in the no-starter added treatment rather than in 28 2 Decenal * 0.25 the P. acidilactici UP02 treated tempoyak. The values 29 2-pentene * 0.25 generated in the experiment might be caused by the 30 Germacyclobutane,1,1-dimethyl * 0.19 presence of other microflora at initial fermentation, 31 Unknown 1.36 * besides LAB. Many microflora such as fungi were able 32 Glycine, methyl ester * 3.04 to produce enzymes, which in turn, degraded 33 Unknown * 1.28 carbohydrates to simple sugars such as glucose and 34 lauric acid, ethyl ester * 0.14 fructose. The aril of durian is known to contain about 35 Unknown 0.88 * 33% carbohydrates on a fresh weight basis, of which 36 Tetradecanoic acid, ethyl ester * 0.1 about one third is probably starch 30 . In the P. acidilactici 37 Hexadecanoic acid, ethyl ester * 0.35 UP02 treatment, the decreasing value of reducing * not found sugars, in this experiment, was probably due to the high ethylthiophosphynil-3- aminopyridine: tetradecanoic rate of consumption by the LAB during fermentation. P. acid ethyl ester; hexadecanoic acid ethyl ester; 4,6 acidilactici UP02 was present in high amounts since the dimethyl-1,2,3,5,5-tetrathiacyclohexane; methaneth- beginning of fermentation. The growth kinetics of YULIANA & GARCIA: INFLUENCE OF P. ACIDILACTICI ON FLAVOUR OF TEMPOYAK 309

different among the treatments when it came to aroma and sourness, the results revealed that samples with P. acidilactici UP02 treatment had higher scores for sourness than other samples. This might be related to the higher acceptability of panelists to the samples treated with P. acidilactici UP02 .

Conclusions Generally, flavour of tempoyak (fermented durian) was influenced by the addition of P. acidilactici UP02 as a starter. Addition of P. acidilactici UP02 in tempoyak fermentation decreased the quantity of sulphur components, increased various non-sulphur Fig. 1—Changes in reducing sugars (%) (wet basis) during compounds, values of non-volatile acidity, and the fermentation of tempoyak with and without P. acidilactici. content of organic acids. The flavour components of tempoyak with P. acidilactici UP02 treatment were Table 4—Sensory evaluation of tempoyak inoculated with and observed to have 48 compounds, although, those with without Pediococcus acidilactici no-starter treatments had 22 compounds. The patterns

Parameters Treatments of reducing sugars in both the samples from day-0 to day-8 of the fermentation period were similar. The Pediococcus No-starter added tempoyak prepared by starter with P. acidilactici Sourness 3.1a 3.6ab UP02 was more acceptable than the no-starter Aroma 3.3a 3.4a treatment. General acceptability 3.6a 4.13b microorganisms present in the samples determined the Acknowledgement consumption rate of reducing sugars, which resulted in The authors thank SEARCA, IFST UPLB and the different reducing sugar contents among the treatments. University of Lampung for supporting this work. A general decease in reducing sugars was also noted in the fermentation of carrot and other foods 25 . References 1 Irwandi & Che-Man Y B, Durian leather: Development, Sensory Evaluation properties and storage stability, J Food Qual, 19 (1996) 439- The sensory score of tempoyak as evaluated by an 489. 18-member panel is given in Table 4. Analysis of 2 Ganjar I, Fermentation of the Far East, in Encyclopedia of variance of the sensory means a score of different food microbiology , edited by R K Robinson, C A Batt and P D Patell (Academic Press, London) 2000, 722. treatments. There is no significant difference among the 3 Battcock M & Ali S A, Fermented fruits and vegetables, a samples as tested at the 0.05 level of significance for global perspective, Chapter 5, FAO Agricultural Services sourness or aroma. However, there was a significant Bull 134 (FAO, Rome) 1998, 2. difference among treatments for general acceptability. 4 Yuliana N, Biochemical changes in fermented durian (Durio zibethinus Murr). Ph D Thesis. University of the Philippines, The P. acidilactici UP02 inoculated samples were more Los Banos, Laguna, Philippines, 2004. acceptable than those with no-starter treatment. 5 Yuliana N, Organic acids component of tempoyak In general, the results of the sensory evaluation (fermented durian), J Teknologi dan Industri Pangan, 16 revealed that the judges were not able to distinguish any (2005) 90-95. difference among the treatments on sourness and aroma. 6 Merican Z, Malaysian tempoyak, in Handbook of indigenous fermented foods, edited by K H Steinkraus, R E Cullen, C S This might be attributed to the fact that 8-d fermented Pederson, L F Nellis and B K Gavitt (Marcel Dekker, New samples were presented in the sensory, wherein, based York) 1997, 128-130. on their biochemical analysis, pH, and acidity were not 7 Halim D, Study of chemical and microbilogical changes in significantly different among the treatments. Besides, tempoyak during fermentation (Minithesis, Institut Pertanian Bogor, Indenesia) 1985. the predominant component present in all the samples 8 Nurainy F, Chemical and microbiological aspect of was basically the same, that is, sulphur compounds. tempoyak fermentation . Abstract of BS Thesis. University of Even though sensory attributes were not significantly Gadjah Mada (UGM), Yogyakarta, 1991. 310 INDIAN J BIOTECHNOL, JULY 2009

9 Amin A M, Jaafar Z & Khim N L, Effect of salt on tempoyak Spoelstra S F, Faber F et al , Anaerobic conversion of lactic fermentation and sensory evaluation, J Biol Sci , 4 (2004) 650- acid to acetic acid and 1,2- propanediol by Lactobacillus 653. buchneri, Appl Environ Microbiol, 67 (2001) 125-132. 10 Leisner J J, Vancanneyy M, Rusul B, Lefebre K, Pot B et al , 20 AOAC. Official methods of analysis of the association of Identification of lactic acid bacteria constituting the official analytical chemist , Chapter 28 (Association of Official predominating microflora in an acid-fermented condiment Analytical Chemists, Washington DC) 2000, 9. (tempoyak) in Malaysia, Int J Food Microbiol , 63 (2001) 149- 21 Nelson N, A photometric adaptation of the Somogyi method 157. for the determination of glucose, J Biol Chem , 153 (1994) 375- 11 Issa Z M, Molecular characterization of Lactobacillus 380. plantarum isolated from Malaysian fermented foods. Abstract 22 Kim H J & Sohn K H, Flavour compounds of dongchimi of MS Thesis, University of Putra, Malaysia, 2000. by different fermentation temperature and salt concentration, 12 Wirawati C U, Potential of lactic acid bacteria isolated from Food Sci Biotechnol, 10 (2001) 236-240. tempoyak as probiotic . MS Thesis, Institute of Pertanian 23 Mabesa L B, Sensory evaluation of foods: Principles and Bogor, Indonesia) 2002. methods (Institute of Food Science and Technology, UPLB. 13 Leisner J J, Vancanneyy M, Lefebvre K, Vandemeulebroecke Laguna, Philippines) 1986, 43-45. K, Hoste B et al , Lactobacillus durianis sp nov, isolated from 24 Ray B & Hoover D G, Pediocins, in Bacteriocins of lactic acid an acid-fermented condiment (tempoyak) in Malaysia, Int J bacteria , edited by D G Hoover and L R Steensen (Academic Syst Evol Microbiol , 52 (2002) 927-931. Press, San Diego) 1993, 181-183. 14 Leal-Sanchez M V, Ruiz-Barba J L, Sanchez A H, Rejano L, 25 Steinkraus K H, Cullen R E, Pederson C S & Gavitt B K, Jimenez-Diaz R et al , Fermentation profile and optimization of Handbook of indigenous fermented foods (Marcel Dekker, green olive fermentation using Lactobacillus plantarum New York) 1983, 669. LPCO10 as a starter culture, J Food Microbiol , 20 (2003) 421- 26 Baldry J, Dougan J & Howard G E, Volatile flavouring 430. constituents of durian, Phytochemistry , 11 (1972) 2081-2084. 15 Wang Y-C, Yu R-C & Chou C-C, Antioxidative activities of 27 Moser R, Duvel D & Grevet R, Volatile constituents and fatty soymik fermented with lactic acid bacteria and bifidobacteria, acid composition of lipids in Durio zibethinus , Phytochemistry, J Food Microbiol , 23 (2006) 128-135. 19 (1980) 79-81. 16 Yin L-J, Pan C-L & Jiang S-T, Effect of lactic acid bacterial 28 Weenen H, Koolhaas W E & Apriyantono A, Sulphur- fermentation on the characteristics of minced mackerel, J Food containing volatiles of durian fruits ( Durio zibethinus Murr.), J Sci , 67 (2002)786-791. Agric Food Chem , 44 (1996) 3291-3293. 17 Cogan T M, Flavour production by dairy starter cultures, Appl 29 Martin F W, Durian and Mangosteen, in Tropical and Bacteriol, 79 (1995) 49S-64S. subtropical fruits: Composition, properties and uses , edited by 18 Ramos A, Jordan K N, Cogan T M & Santos H, 13 C-NMR S Nagy and P E Shaw (AVI Publishing Inc, Westport, studies of citrate and glucose co-metabolism by Lactococcus Connecticut) 1980, 407-414. lactis, Appl Environ Microbiol, 60 (1994) 1739-1748. 30 Brown M J, Durio, a bibliographic review (APO International 19 Oude-Elferink S J W H, Krooneman J, Gottschal J C, Plant Genetic Resources Institute, New Delhi) 1977, 1-188.