Effect of heat shock on the fatty acid and protein profiles of Cronobacter sakazakii BCRC 13988 as well as its growth and survival in the presence of various carbon, nitrogen sources and disinfectants.

In the present study, Cronobacter sakazakii, a foodborne pathogen, was first subjected to heat shock at 47 °C for 15 min. Effect of heat shock on the fatty acid and protein profiles, carbon and nitrogen source requirements as well as the susceptibilities of C. sakazakii to Clidox-S, a chlorine-containing disinfectant and Quatricide, a quaternary ammonium compound were investigated. Results revealed that heat shock increased the proportion of myristic acid (14:0), palmitic acid (16:0) and the ratio of saturated fatty acid to unsaturated fatty acid, while reducing the proportion of palmitoleic acid (16:1) and cis-vacceric acid (18:1). In addition, eleven proteins showed enhanced expression, while one protein showed decreased expression in the heat-shocked compared to the non-heat-shocked cells. Non-heat-shocked cells in the medium supplemented with beef extract exhibited the highest maximum population. On the contrary, the highest maximum population of heat-shocked C. sakazakii was noted in the medium having either tryptone or yeast extract as the nitrogen source. Among the various carbon sources examined, the growth of the test organism, regardless of heat shock, was greatest in the medium having glucose as the carbon source. Furthermore, heat shock enhanced the resistance of C. sakazakii to Clidox-S or Quatricide.

Susceptibility of Vibrio parahaemolyticus to disinfectants after prior exposure to sublethal stress.

In the present study, Vibrio parahaemolyticus 690 in phosphate buffered-saline containing 3% NaCl was subjected to sublethal stresses: heat shock at 42 °C for 15 min, acid adaptation at pH 5.0 for 30 min, or cold shock at 20 °C for 4 h. The effect of sublethal stress on the susceptibility of V. parahaemolyticus to a chlorine-containing disinfectant (Clidox-S) and a quaternary ammonium compound (Quatricide) at 25 and 40 °C was investigated. It was found that the sublethal stresses examined enhanced the resistance of V. parahaemolyticus 690 to both disinfectants. Depending on the kinds of sublethal stress, V. parahaemolyticus 690 showed various degrees of enhanced resistance to disinfectants. Furthermore, the phenomenon of enhanced resistance to the disinfectants was more marked at 40 than at 25 °C.

Effect of ethanol shock pretreatment on the tolerance of Cronobacter sakazakii BCRC 13988 exposed to subsequent lethal stresses.

Cronobacter spp., formerly Enterobacter sakazakii, are human pathogens. They are the etiological agent of life-threating bacterial infections in infants. In this study, the survival behavior of C. sakazakii Bioresources Collection and Research Center (BCRC) 13988 in the presence of various ethanol concentrations was first examined. Besides, the test organism was subjected to treatment with 5% ethanol for 60 min (ethanol shock). The effect of ethanol shock on the resistance of C. sakazakii to lethal stresses, including high ethanol concentration (15%), low temperature (4°C and -20°C), high temperature (51°C) and high acidity (pH 3.3), was investigated. Results revealed that 4-5% ethanol is the maximum concentration that will allow C. sakazakii BCRC 13988 to grow in trypticase soy broth (TSB). Etthanol at 6% and 7% or more, respectively, exerted bacteriostatic and bactericidal effects, respectively, on the test organism. Although ethanol shock did not affect the resistance of C. sakazakii to a refrigerated temperature (4°C), the ethanol-shocked C. sakazakii survived better under other lethal stress conditions. After 50 min of exposure to 15% ethanol, the ethanol-shocked C. sakazakii showed a survival percentage of 16.11%, which was a 6400-fold increase over the control cells (<0.01%). On the other hand, the ethanol-shocked C. sakazakii exhibited a 45-fold higher survival after 120-min exposure to 51°C. At the end of the 7-day storage at -20°C, the ethanol-shocked cells exhibited a survival percentage of 0.25% which was significantly (p<0.05) higher than that (less than 0.01%) of the control. Additionally, the ethanol-shocked cells showed a survival percentage of 13.80% compared to only 1.60% noted with the control cells after exposure to pH 3.3 for 60 min.

Antiproliferative and anticytotoxic effects of cell fractions and exopolysaccharides from Lactobacillus casei 01.

Cell fractions including heat-treated cells, crude cell walls, intracellular extracts and exopolysaccharides (EPSs) obtained from Lactobacillus casei 01 were first studied for their effects on the proliferation of human intestinal epithelial cells, intestine 407 and the human colon cancer cell, HT-29. Their effects on the cytotoxicity of 4-nitroquinoline 1-oxide (4-NQO) against intestine 407 were further investigated. The results revealed that EPS exhibited the highest antiproliferation activity on HT-29 cells while the viability of intestine 407 cells was not affected by EPS at a concentration of 5-50µg/mL. It was also noted that all the cell fractions and EPS from L. casei 01 reduced the cytotoxicity of 4-NQO against intestine 407 with EPS showing the highest anticytotoxic activity. Additionally, it was found that EPS might exert blocking and bioanticytotoxic effects by both adjusting the function of intestine 407 and repairing the 4-NQO-damaged cells, thus reducing cytotoxicity of 4-NQO.

Atmospheric cold plasma-assisted pineapple peel waste hydrolysate detoxification for the production of bacterial cellulose.

Toxic compounds in pineapple peel waste hydrolysate (PPWH), namely formic acid, 5-hydroxymethylfurfural (HMF), and furfural, are the major predicament in its utilization as a carbon source for bacterial cellulose (BC) fermentation. A rapid detoxification procedures using atmospheric cold plasma (ACP) technique were employed to reduce the toxic compounds. ACP treatment allows the breakdown of toxic compounds without causing excessive breakdown of sugars. Herein, the performance of two available laboratory ACP reactors for PPWH detoxification was being demonstrated. ACP-reactor-1 (R1) runs on plasma power of 80-200 W with argon (Ar) plasma source, while ACP-reactor-2 (R2) runs at 500-600 W with air plasma source. Treatment in R1, at 200 W for 15 min, results in 74.06%, 51.38%, and 21.81% reduction of furfural, HMF, and formic acid. Treatment in R2 at 600 W gives 45.05%, 32.59%, and 60.41% reductions of furfural, HMF, and formic acid. The BC yield from the fermentation of Komagateibacter xylinus in the R1-treated PPWH, R2-treated PPWH, and untreated-PPWH is 2.82, 3.82, and 2.97 g/L, respectively. The results show that ACP treatment provides a novel detoxified strategy in achieving agricultural waste hydrolysate reuse in fermentation. Furthermore, the results also imply that untreated PPWH can be an inexpensive and sustainable resource for fermentation media supplementation.

Bioactive compounds with anti-oxidative and anti-inflammatory activities of hop extracts.

The aim of this study is to simultaneously evaluate anti-oxidative and anti-inflammatory activities of the hop extracts by different solvents. Hop water extract (HWE) and hop ethanol extracts (HEEs) were prepared by extracting hop pellets with hot water at 90 °C and ethanol solutions (55%, 75%, and 95%), respectively. Bioactive compound such as α-acid, ß-acid, total phenolic, and total flavonoid contents were determined. All the HEEs showed higher anti-oxidative activities than the HWEs. The HEEs showing the highest anti-oxidative activities are different in the experiments with different free radicals. For anti-inflammatory activities, both the HWE and HEEs decreased NO productions. HWE decreased TNF-α and IL-6 secretion but showed no effect on IL-1ß, while HEEs decreased IL-1ß and IL-6 secretion but increased TNF-α secretion. Except for TNF-α secretion, the HEEs showed higher anti-inflammatory activities than the HWE. Future work is to explore the possible mechanism to improve the ethanol extraction procedure.

Protein expression in Vibrio parahaemolyticus 690 subjected to sublethal heat and ethanol shock treatments.

Cells of Vibrio parahaemolyticus 690 were subjected either to heat shock at 42 degrees C for 45 min or to ethanol shock in the presence of 5% ethanol for 60 min. The protein profiles of the unstressed and stressed V. parahaemolyticus cells were compared. Additionally, the induction of DnaK- and GroEL-like proteins in the unstressed and stressed cells of V. parahaemolyticus was also examined. Analysis with one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated that three proteins with molecular masses of 93, 77, and 58 kDa were induced by both heat shock and ethanol shock. The protein patterns revealed by two-dimensional electrophoresis were more detailed than those revealed by one-dimensional SDS-PAGE. It was found that heat shock and ethanol shock affected the expression of a total of 28 proteins. Among them, four proteins with molecular masses of 94, 32.1, 26.7, and 25.7 kDa were enhanced by both heat shock and ethanol shock. Furthermore, immunoblot analysis showed the presence of a GroEL-like protein with a molecular mass of 61 kDa in the test organism, with the heat-shocked and ethanol-shocked cells producing a GroEL-like protein in a larger quantity than the unstressed cells. However, DnaK-like protein was not detectable in either the unstressed or the stressed cells.

Optimization of culture conditions for gamma-aminobutyric acid production in fermented adzuki bean milk.

γ-Aminobutyric acid (GABA), a nonprotein amino acid, is widely distributed in nature and fulfills several physiological functions. In this study, various lactic acid strains commonly used to produce fermented milk products were inoculated into adzuki bean milk for producing GABA. The high GABA producing strain was selected in further experiment to improve the GABA production utilizing culture medium optimization. The results demonstrated that adzuki bean milk inoculated with Lactobacillus rhamnosus GG increased GABA content from 0.05 mg/mL to 0.44 mg/mL after 36 hours of fermentation, which showed the greatest elevation in this study. Furthermore, the optimal cultural condition to adzuki bean milk inoculated with L. rhamnosus GG to improve the GABA content was performed using response surface methodology. The results showed that GABA content was dependent on the addition of galactose, monosodium glutamate, and pyridoxine with which the increasing ratios of GABA were 23-38%, 24-68%, and 8-36%, respectively. The optimal culture condition for GABA production of adzuki bean milk was found at the content of 1.44% galactose, 2.27% monosodium glutamate, and 0.20% pyridoxine. Under the optimal cultural condition, the amount of GABA produced in the fermented adzuki bean milk was 1.12 mg/mL, which was 22.4-fold higher than that of the unfermented adzuki bean milk (0.05 mg/100 mL). The results suggested that the optimized cultural condition of adzuki bean milk inoculated with L. rhamnosus GG can increase GABA content for consumers as a daily supplement as suggested.

Protective and Detoxifying Effects Conferred by Dietary Selenium and Curcumin against AFB1-Mediated Toxicity in Livestock: A Review.

Aflatoxin B1 (AFB1), among other aflatoxins of the aflatoxin family, is the most carcinogenic and hazardous mycotoxin to animals and human beings with very high potency leading to aflatoxicosis. Selenium is an essential trace mineral possessing powerful antioxidant functions. Selenium is widely reported as an effective antioxidant against aflatoxicosis. By preventing oxidative liver damage, suppressing pro-apoptotic proteins and improving immune status in AFB1 affected animals; selenium confers specific protection against AFB1 toxicity. Meticulous supplementation of animal feed by elemental selenium in the organic and inorganic forms has proven to be effective to ameliorate AFB1 toxicity. Curcumin is another dietary agent of importance in tackling aflatoxicosis. Curcumin is one of the major active ingredients in the tubers of a spice Curcuma longa L., a widely reported antioxidant, anticarcinogenic agent with reported protective potential against aflatoxin-mediated liver damage. Curcumin restricts the aflatoxigenic potential of Aspergillusflavus. Curcumin inhibits cytochrome P450 isoenzymes, particularly CYP2A6 isoform; thereby reducing the formation of AFB1-8, 9-epoxide and other toxic metabolites causing aflatoxicosis. In this review, we have briefly reviewed important aflatoxicosis symptoms among animals. With the main focus on curcumin and selenium, we have reviewed their underlying protective mechanisms in different animals along with their extraction and production methods for feed applications.

Acid adaptation affects the viability of Salmonella typhimurium during the lactic fermentation of skim milk and product storage.

In this study, Salmonella typhimurium was acid adapted at pH 5.5 for 4 h. The viability of the acid-adapted and non-adapted cells of S. typhimurium was investigated both during the lactic fermentation of skim milk with Streptococcus thermophilus or Lactobacillus bulgaricus, and during the storage of lactic fermented milk products at 5 degrees C. It was found that the viable population of S. typhimurium, regardless of acid adaptation, increased in skim milk during the initial 24 h of lactic fermentation and then declined. However, the viable population of acid-adapted S. typhimurium was significantly higher (P<.05) than that of non-adapted cell at the end of 48 h of fermentation. Acid-adapted cells of S. typhimurium were also found to have survived better than non-adapted cells in the S. thermophilus-prepared fermented milk and two commercial lactic fermented milk products. The viability of the acid-adapted and non-adapted S. typhimurium at 5 and 37 degrees C in cell-free fermented milks that had their pHs adjusted to 6.4 and skim milk (pH 6.4) was further investigated. Results revealed that acid adaptation, in addition to enhancing acid tolerance, reduced the susceptibility of S. typhimurium to refrigerated temperature and other detrimental factors which might be present in lactic fermented milk products. These responses all contribute to the enhanced survival of acid-adapted S. typhimurium in the lactic fermented milk products observed in the present study.

Possible mechanisms of antimutagenicity in fermented soymilk prepared with a coculture of Streptococcus infantis and Bifidobacterium infantis.

The possible mechanisms of antimutagenicity against 4-nitroquinoline-N-oxide (4-NQO; a direct mutagen) and 3,2'-dimethyl-4-amino-biphenyl (DMAB; an indirect mutagen) were examined in fermented soymilk prepared with a coculture of Streptococcus thermophilus and Bifidobacterium infantis. The antimutagenicity in the fermented soymilk was not due to the bioantimutagenic effect of modulation of DNA repair processes. The mutagenicity of DMAB decreased with increased preincubation of fermented soymilk and the DMAB metabolite but not with intact DMAB or an S9 mixture. Mutagenicity of 4-NQO was not affected by preincubation of fermented soymilk with this mutagen. Mutagenicity of both 4-NQO and DMAB was reduced when Salmonella Typhimurium TA 100 was pretreated with fermented soymilk, indicating that fermented soymilk affected the function of the bacterial cell, which might also lead to reduced mutagenicity of the tested mutagens. Desmutagenic and blocking effects were the main mechanisms of antimutagenicity in the fermented soymilk against DMBA. In contrast, the antimutagenic effect of the fermented soymilk on 4-NQO was primarily due to a blocking effect.

Hydrolysis of isoflavone in black soy milk using cellulose bead as enzyme immobilizer.

The establishment of a catalytic system to enrich isoflavone aglycones in black soybean milk was investigated in this study. Beta-glucosidase, which was covalently immobilized onto cellulose beads, exhibited a significant efficiency for the conversion of 4-nitrophenyl ß-d-glucuronide to p-nitrophenol over the sol-gel method. The Michaelis constant (Km) of the cellulose bead enzymatic system was determined to be 1.50±0.10 mM. Operational reusability of the cellulose bead enzymatic system was justified for more than 10 batch reactions in black soy milk. Moreover, the storage stability verification indicated that the cellulose bead catalytic system was able to sustain its highest catalytic activity for 10 days. High-performance liquid chromatography results demonstrated that this enzymatic system required only 30 minutes to achieve complete isoflavone deglycosylation, and the aglycone content in the total isoflavones in black soy milk was enriched by 67% within 30 minutes by the cellulose bead enzymatic system.

Bisdemethoxycurcumin Inhibits Adipogenesis in 3T3-L1 Preadipocytes and Suppresses Obesity in High-Fat Diet-Fed C57BL/6 Mice.

Obesity is caused by excessive accumulation of body fat and is closely related to complex metabolic diseases. Adipogenesis is a key process that is required in adipocyte hypertrophy in the development of obesity. Curcumin (Cur) has been reported to inhibit adipocyte differentiation, but the inhibitory effects of other curcuminoids present in turmeric, such as demethoxycurcumin (DMC) and bisdemethoxycurcumin (BDMC), on adipogenesis have not been investigated. Here, we investigated the effects of curcuminoids on adipogenesis and the molecular mechanisms of adipocyte differentiation. Among three curcuminoids, BDMC was the most effective suppressor of lipid accumulation in adipocytes. BDMC suppressed adipogenesis in the early stage primarily through attenuation of mitotic clonal expansion (MCE). In BDMC-treated preadipocytes, cell cycle arrest at the G0/G1 phase was found after initiation of adipogenesis and was accompanied by downregulation of cyclin A, cyclin B, p21, and mitogen-activated protein kinase (MAPK) signaling. The protein levels of the adipogenic transcription factors peroxisome proliferator-activated receptor (PPAR)γ and CCAAT/enhancer-binding proteins (C/EBP)α were also reduced by BDMC treatment. Furthermore, 0.5% dietary BDMC (w/w) significantly lowered body weight gain and adipose tissue mass in high-fat diet (HFD)-fed mice. The results of H&E staining showed that dietary BDMC reduced hypertrophy in adipocytes. These results demonstrate for the first time that BDMC suppressed adipogenesis in 3T3-L1 adipocytes and prevented HFD-induced obesity. Our results suggest that BDMC has the potential to prevent obesity.

Fatty acid composition, cell morphology and responses to challenge by organic acid and sodium chloride of heat-shocked Vibrio parahaemolyticus.

Vibrio parahaemolyticus 690, a clinical strain, was subjected to heat shock at 42 degrees C for 45 min. The fatty acid profile and recovery of the heat-shocked cells of V. parahaemolyticus on TSA-3.0% NaCl, APS agar (Alkaline peptone salt broth supplemented with 1.5% agar) and TCBS (Thiosulfate-citrate-bile salts-sucrose agar) were compared with those of the nonheat-shocked cells. Furthermore, the morphology of V. parahaemolyticus and survival in the presence of various organic acids (25 mM acetic acid, lactic acid, citric acid or tartaric acid) and NaCl (0.1% and 20.0%) as influenced by heat shock treatment were also investigated. It was found that heat shock caused a change in the proportions of the unsaturated and saturated fatty acid. The ratio of saturated fatty acids to unsaturated fatty acids observed on heat-shocked V. parahaemolyticus cells was significantly (p<0.05) higher than that on the control cells. Extensive cell-wall pitting and cell disruption, representing cell-surface damage, were also observed on the cells which were subjected to heat shock treatment. Recovery of heat-shocked cells of V. parahaemolyticus was significantly less on TCBS and APS agar than on TSA-3.0% NaCl. Heat shock decreased the tolerance of V. parahaemolyticus to organic acids. The extent of decreased acid tolerance observed on heat-shocked cells varied with the organic acid tested. While heat shock increased the survival of V. parahaemolyticus in the presence of 0.1% NaCl and made the test organism more susceptible to 20.0% NaCl than the control cells.

The implementation of a Hazard Analysis and Critical Control Point management system in a peanut butter ice cream plant.

To ensure the safety of the peanut butter ice cream manufacture, a Hazard Analysis and Critical Control Point (HACCP) plan has been designed and applied to the production process. Potential biological, chemical, and physical hazards in each manufacturing procedure were identified. Critical control points for the peanut butter ice cream were then determined as the pasteurization and freezing process. The establishment of a monitoring system, corrective actions, verification procedures, and documentation and record keeping were followed to complete the HACCP program. The results of this study indicate that implementing the HACCP system in food industries can effectively enhance food safety and quality while improving the production management.

Susceptibility of Vibrio parahaemolyticus to various environmental stresses after cold shock treatment.

Vibrio parahaemolyticus was subjected to cold shock treatment at 20 or 15 degrees C for 2 or 4 h. The effect of cold shock on the survival of V. parahaemolyticus subjected to subsequent low temperature (5 and -18 degrees C) and other adverse conditions (47 degrees C, 6 ppm crystal violet, 1000 ppm H(2)O(2), 25 mM acetic acid and 25 mM lactic acid) was investigated. Regardless of the cold shock treatment, survival of V. parahaemolyticus increased when stored at 5 or -18 degrees C, while no increase in survival was noted for cells cold shocked in the presence of chloramphenicol. Cold shock treatment under the conditions tested, in general, enabled V. parahaemolyticus cells to survive better following subsequent challenge by crystal violet, while the cold-shocked organism was more susceptible to high temperature (47 degrees C), H(2)O(2) and organic acids (lactic and acetic acid) than the non-shocked cells. Furthermore, the temperature and time of the cold shock treatment affected the cold shock response of V. parahaemolyticus.

Effect of iron limitation on the growth and cytotoxin production of Salmonella choleraesuis SC-5.

This study investigated the effect of iron limitation on the growth and cytotoxin production of Salmonella choleraesuis and examined the iron-accruing capability of various Salmonella strains. It was found that the growth of S. choleraesuis SC-5 was retarded by the presence of iron-chelating agents, 2,2'-dipyridyl or ethylenediamine di-o-hydroxyphenylactic acid (EDDA). Addition of 2,2'-dipyridyl to Trypticase soy broth (TSB) resulted in a smaller maximum population of S. choleraesuis noted at the stationary phase, while addition of EDDA in TSB only caused an extended period of lag phase. A significant increase in cytotoxin production was found when S. choleraesuis SC-5 was cultured in iron-limited TSB containing 2,2'-dipyridyl. On the other hand, pre-culture in an iron-limited medium increased the growth of S. choleraesuis SC-5 in mouse serum with or without complement inactivated. Testing with a plate assay method revealed that the ability and efficiency of Salmonella to acquire iron under iron-limited condition varied with strains, and the kinds and dosages of iron-containing compounds present.

Viability of lactic acid bacteria and bifidobacteria in fermented soymilk after drying, subsequent rehydration and storage.

To develop a probiotic dietary adjunct, soymilk fermented with various combinations of lactic acid bacteria (Streptococcus thermophilus and Lactobacillus acidophilus) and bifidobacteria (Bifidobacterium longum and Bifidobacterium infantis) was subjected to freeze-drying and spray-drying. Survival of the starter organisms during the drying process, subsequent rehydration at different temperatures and during a 4-month period of storage under different storage conditions was examined. After freeze-drying, lactic acid bacteria and bifidobacteria exhibited a survival percent of 46.2-75.1% and 43.2-51.9%, respectively, higher than that noted after spray-drying. Regardless of the drying condition, S. thermophilus showed a higher percentage of survival than L. acidophilus, while B. longum survived better than B. infantis. Further study with soymilk fermented with S. thermophilus and B. longum revealed that the freeze-dried and spray-dried fermented soymilk rehydrated at 35-50 degrees C and 20 degrees C, respectively, was optimum for the recovery of the starter organisms. Both S. thermophilus and B. longum survived better in the freeze-dried than the spray-dried fermented soymilk during storage. A higher percent of survival was also noted for both the starter organisms when the dried fermented soymilk was stored at 4 degrees C than 25 degrees C. Holding the dried fermented soymilk in the laminated pouch enabled S. thermophilus and B. longum to exhibit a higher percentage of survival than in the deoxidant- and desiccant-containing glass or polyester (PET) bottle. Among all the packaging materials and storage temperatures tested, starter organisms were most stable in the dried fermented soymilk held in laminated pouch and stored at 4 degrees C. Under this storage condition, S. thermophilus and B. longum showed a survival percentage of 51.1% and 68.8%, respectively, in the freeze-dried fermented soymilk after 4 months of storage. Meanwhile, S. thermophilus and B. infantis in the spray-dried fermented soymilk showed a survival percent of 29.5% and 57.7%, respectively.

Determinations of the antimutagenic activities of several probiotic bifidobacteria under acidic and bile conditions against benzo[a]pyrene by a modified Ames test.

Antimutagenic activities of six bifidobacteria, after acidic and bile treatment mimicking gastrointestinal conditions, against benzo[a]pyrene (B[a]P) were determined by a modified Ames test using Salmonella typhimurium TA 100. Results showed that when bifidobacteria were treated at pH 2.0 for 3 h or 1% bile for 6 h, their antimutagenic activities against B[a]P were increased as compared to controls at pH 7.0 for 0 h. After sequential acidic pH and bile treatments, Bifidobacterium lactis Bb-12 displayed the highest antimutagenic activity (71.5%), although its viable cell number was less than 2.0 log cfu/ml. The antimutagenic activity of B. lactis Bb-12 against B[a]P was increased as pH values were increased from 2.0 to 7.0, and reaction time was extended from 1 to 3 h. However, antimutagenic activity was decreased as bile salt concentration was increased from 0.5% to 2.0%. The antimutagenic activity of B. lactis Bb-12 against B[a]P was increased in the presence of whole milk (WM), semiskimmed milk (SSM) and skimmed milk (SM). When B. lactis Bb-12 was preincubated with B[a]P and milk substrates, its antimutagenic activity was increased to 99-100%.

Enrichment of two isoflavone aglycones in black soymilk by using spent coffee grounds as an immobiliser for ß-glucosidase.

Spent coffee grounds, discarded as environmental pollutants, were adopted as enzyme immobilisation solid carriers instead of commercialised solid supports to establish an economical catalytic system. ß-Glucosidase was covalently immobilised onto spent coffee grounds for the conversion of isoflavone glycosides into their aglycones in black soymilk. Optimum conditions were determined to be 40°C and pH 6 using 4-nitrophenyl ß-D-glucuronide as an indicator. Operational reusability was confirmed for more than 30 batch reactions and the storage stability was capable of sustaining its highest catalytic activity for 20 days. The kinetic parameters including rate constant (K), time (τ(50)) in which 50% of isoflavone deglycosylation was reached, and time (τ(complete)) required to achieve complete isoflavone deglycosylation, were 0.16±0.02 min(-1), 4.54±0.32 min, 60 min for daidzin and 0.16±0.02 min(-1), 2.28±0.11 min, 60 min for genistin, respectively. The total aglycone content in black soymilk was enriched by 67.14±0.60% in the enzymatic treatment of 60 min duration.