Solid state fermentation to obtain vegetable products bio-enriched with isoflavone aglycones using lactic cultures / Fermentación en sustrato sólido utilizando cultivos lácticos para la obtención de productos vegetales bioenriquecidos con isoflavonas agliconas

The consumption of soybean isoflavones (IS) is associated with several beneficial properties on human health. Some lactic acid bacteria possess ß-glucosidase enzyme, that allows to obtain the active form of IS (aglycone). The solid state fermentation (SSF) has received great attention in the last years in order to obtain several valuable compounds. SSF, using soybean as substrate and Lactobacillus rhamnosus CRL 981 as starter, was studied in the present work. Sucrose was added into soybean paste to study the effect on the behavior of the selected strain. The development of L. rhamnosus CRL 981 through pH and recount measures, sugar intake, organic acid production, ß-glucosidase activity and IS conversion were analyzed. No significant differences in growth and acidity were observed between soybean pastes with and without sucrose added, but the production of lactic acid was higher in the latter paste. The ß-glucosidase activity was detected in both pastes and the complete hydrolysis of IS at 12 h of fermentation was observed. Also, this strain was able to increase the free amino acids in soybean paste. SSF, using soybean as substrate and L. rhamnosus CRL 981 as starter culture, is an alternative process to obtain a soybean product bio-enriched in active IS with attractive nutritional characteristics.

El consumo de isoflavonas de soja (IS) está asociado a diversos beneficios para la salud humana. Ciertas bacterias lácticas poseen la enzima ß-glucosidasa, que permite obtener la forma bioactiva (agliconas) de las IS. La fermentación en sustrato sólido (FSS) ha recibido gran atención en los últimos anos debido a sus numerosas ventajas, y permite la obtención de productos con valor agregado. En el presente trabajo se estudió la FSS utilizando soja como sustrato y Lactobacillus rhamnosus CRL981 como cultivo iniciador. Con el fin de estudiar el efecto de una fuente de carbono externa sobre el comportamiento de la cepa seleccionada, se adicionó sacarosa a la pasta de soja. Se evaluó el crecimiento de L. rhamnosus CRL 981 a través de medidas de pH y recuento en placa. Además, se analizó el consumo de azúcares, producción de ácidos orgánicos, actividad ß-glucosidasa y conversión de IS. No se observaron diferencias significativas en el crecimiento y acidez entre las pastas de soja sin adición de sacarosa y con ella, sin embargo, la producción de ácido láctico fue mayor en esta última. La actividad de ß-glucosidasa se detectó en ambas pastas y se observó la hidrólisis completa de IS a las 12 h de fermentación. Además, esta cepa fue capaz de aumentar los aminoácidos libres en la pasta de soja. La FSS, utilizando soja como sustrato y L. rhamnosus CRL 981 como cultivo iniciador, es un proceso alternativo para obtener un producto de soja bioenriquecido en IS bioactivas con características nutricionales atractivas.

Production of puerarin and isoflavones in cell suspension cultures of Pueraria lobata (Willd.): effects of medium supplementation with casein hydrolysate and coconut milk.

Callus induced from leaf explants of Pueraria lobata seedlings were suspended in Gamborg B5 medium supplemented with 1 mg l(-1) 2,4-dichlorophenoxyacetic acid, 1 mg l(-1) naphthalene acetic acid, 0.5 mg l(-1) kinetin and 30 g l(-1) sucrose. The effects of coconut milk and casein hydrolysate (CH) on cell growth and yields of puerarin and isoflavones in cells suspension were studied. The contents of total isoflavones and puerarin in suspension cultures were determined by spectrophotometry and HPLC. Coconut milk (10%, filter sterilized) decreased the growth of cell cultures and the accumulation of total isoflavones, while 0.2% CH promoted the growth of cell cultures and the accumulation and release of puerarin and total isoflavones. The total yield of puerarin and isoflavones were 34% and 40.8% higher than in the control, respectively. The optimum medium for cell cultures of leaves of P. lobata seedlings was B5 liquid medium supplemented with 2% sucrose, 1.0 mg l(-1) 2,4-D, 1.0 mg l(-1) NAA, 0.5 mg l(-1) kinetin and 20 mg l(-1) CH. The procedure use is a potentially useful for the production of isoflavones.

Higher consumption of green tea may enhance equol production.

BACKGROUND: Our previous case-control study revealed that Japanese living in Japan and Koreans living in Korea can be divided into equol producers who have an ability to metabolize daidzein to equol and non-producers, and that the incidence of prostate cancer is higher in the latter group. In the present study, we examined relationships between type of food intake and the capacity for equol production in Japanese subjects. METHODS: The subjects were the individuals analyzed for the ability to produce equol in our previous study and newly registered cases. From December 2000 to December 2002, 276 hospitalized patients were interviewed face-to-face and blood samples were collected before breakfast. These included 122 patients with prostate cancer and 154 age-matched controls. RESULTS: The frequency of equol producers (0.5 ng/ml or more) among cases and controls was 29% and 45%, respectively (p = 0.004). The consumption of soybeans and green tea were significantly higher in equol producers than in the non-producers (p<0.05). By contrast, the consumption of selenium and fiber was significantly lower in equol producers (p<0.05). CONCLUSIONS: Our results suggest that higher consumption of soybean and green tea are strongly related to the establishment of a capacity for equol production.