An Updated Review of Soy-Derived Beverages: Nutrition, Processing, and Bioactivity.

The global market for plant-based drinks is experiencing rapid growth driven by consumer demand for more sustainable diets, including vegetarian and vegan options. Soy beverages in particular are gaining popularity among individuals with lactose intolerance and milk protein allergies. They are considered an excellent source of high-quality protein, vitamin B, unsaturated fatty acids, and beneficial phytochemicals such as phytosterols, soy lecithins, and isoflavones. This review presents a comprehensive market survey of fifty-two soy beverages available in Spain and other European countries. The predominant category among those evaluated was calcium and vitamin-fortified drinks, accounting for 60% of the market. This reflects the need to address the nutritional gap compared to cow's milk and meet essential dietary requirements. The review covers the technological aspects of industrial soy milk production, including both traditional methods and innovative processing techniques. Additionally, it analyzes multiple studies and meta-analyses, presenting compelling evidence for the positive effects of soy beverages on various aspects of health. The review specifically examines the contributions of different components found in soy beverages, such as isoflavones, proteins, fiber, and oligosaccharides. Moreover, it explores controversial aspects of soy consumption, including its potential implications for growth, puberty, fertility, feminization, and the thyroid gland.

Quantitative determination of active Bowman-Birk isoinhibitors, IBB1 and IBBD2, in commercial soymilks.

Naturally-occurring serine protease inhibitors of the Bowman-Birk family exert their potential chemopreventive and/or therapeutic properties via protease inhibition. In this study, we have quantified the amounts of active BBI isoinhibitors, IBB1 and IBBD2, in six commercial soymilks. By using cation exchange chromatography, the BBI isoinhibitors were isolated and their specific trypsin inhibitory activity was used to estimate their amounts in soymilk samples. IBB1 and IBBD2 concentrations ranged from 0.44 to 5.20 and 0.27 to 4.60 mg/100ml of soymilk, respectively; total BBI, considered as the sum of both isoinhibitors, ranged from 0.60 to 9.07 mg/100ml of soymilk. These data show that physiologically relevant amounts of active BBI are present in commercial soymilk and may exert potential health-promoting effects.

Galacto-oligosaccharides derived from lactulose exert a selective stimulation on the growth of Bifidobacterium animalis in the large intestine of growing rats.

There is increasing interest in identifying novel dietary nondigestible carbohydrates capable of modulating the composition and/or metabolic activities of the gut microbiota. This work assessed the differential modulatory influence of novel galacto-oligosaccharides derived from lactulose (GOS-Lu) in comparison with commercial galacto-oligosaccharides derived from lactose (GOS-La) in gut microbiota of growing rats (5 weeks old). Rats were fed either a control diet or diets containing 1% (w/w) of GOS-Lu or GOS-La, and cecal and colonic contents were collected after 14 days of treatment. Compared to controls, GOS-Lu had significantly more bifidobacteria within the large intestine, showing a significant and selective increase of Bifidobacterium animalis in the cecum and colon; however, no significant differences in the number of bifidobacteria among GOS-Lu and GOS-La groups were observed. Both types of GOS significantly increased the number of the Eubacterium rectale / Clostridium coccoides group. These findings support a prebiotic role of galactosyl-fructoses in functional foods.

Monomer and linkage type of galacto-oligosaccharides affect their resistance to ileal digestion and prebiotic properties in rats.

A detailed study was performed to compare the in vivo ileal digestibility and modulatory effects in fecal microbiota of novel galacto-oligosaccharides (GOS) derived from lactulose [GOS-Lu; degree of polymerization (DP) ≥2, 14.0% trisaccharides] and commercial GOS derived from lactose (GOS-La; DP ≥3, 35.1% trisaccharides) in growing rats (5 wk old). Rats were fed either a control diet or diets containing 1% (wt:wt) of GOS-Lu or GOS-La for 14 d. Quantitative analysis of carbohydrates from dietary and ileal samples demonstrated that the trisaccharide fraction of GOS-Lu was significantly more resistant to gut digestion than that from GOS-La, as indicated by their ileal digestibility rates of 12.5 ± 2.6% and 52.9 ± 2.7%, respectively, whereas the disaccharide fraction of GOS-Lu was fully resistant to the extreme environment of the upper digestive tract. The low ileal digestibility of GOS-Lu was due to the great resistance of galactosyl-fructoses to mammalian digestive enzymes, highlighting the key role played by the monomer type and linkage involved in the oligosaccharide chain. The partial digestion of GOS-La trisaccharides showed that glycosidic linkages (1→6) and (1→2) between galactose and glucose monomers were significantly more resistant to in vivo gastrointestinal digestion than the linkage (1→4) between galactose units. The absence of GOS-La and GOS-Lu digestion-resistant oligosaccharides in fecal samples indicated that they were readily fermented within the large intestine, enabling both types of GOS to have a potential prebiotic function. Indeed, compared with controls, the GOS-Lu group had significantly more bifidobacteria in fecal samples after 14 d of treatment. The number of Eubacterium rectale also was greater in the GOS-Lu and GOS-La groups than in controls. These novel data support a direct relationship between patterns of resistance to digestion and prebiotic properties of GOS.

Anti-carcinogenic soyabean Bowman-Birk inhibitors survive faecal fermentation in their active form and do not affect the microbiota composition in vitro.

Bowman-Birk inhibitor (BBI) from soyabeans is a naturally occurring protease inhibitor with potential anti-inflammatory and chemopreventive properties within the gastrointestinal tract (GIT). In a previous paper, we reported that significant amounts of BBI-related proteins reach the terminal ileum functionally and biologically active. We have now investigated: (a) if soyabean BBI is biotransformed by faecal microbiota which would reduce its potential colorectal chemopreventive properties and (b) the potential influence of this protease inhibitor on the modulation of faecal microbiota. In vitro incubation studies of native soyabean BBI at a physiological level (93 microM) with mixed faecal samples of pigs for 24 h at 37 degrees C demonstrated that BBI remains active and its intrinsic trypsin and chymotrypsin inhibitory activities were not significantly influenced by the enzymic or metabolic activity of faecal microbiota. Soyabean BBI did not affect the growth of the different bacterial groups studied (lactobacilli, bifidobacteria, bacteroides, coliforms, enterobacteria, clostridia and total anaerobes). It was concluded that protease inhibitory activities, intrinsically linked to the chemopreventive properties of soyabean BBI, were largely unaffected by faecal microbiota in vitro. BBI retains significance, therefore, as a bioactive compound in the human GIT.

Effect of salt stress on the expression of NHX-type ion transporters in Medicago intertexta and Melilotus indicus plants.

Medicago intertexta and Melilotus indicus, two wild leguminous herbs with different tolerance to salinity were investigated for NaCl-induced changes in the expression level of some Na(+) transporters. M. indicus plants grew well at NaCl concentration from 0 to 400 mM, whereas growth of M. intertexta plants was severely inhibited at NaCl concentrations higher than 100 mM. In M. intertexta, increasing NaCl in the growth media caused a strong increase in Na(+) content concomitant with a decrease in K(+) content in leaves and, above all, roots. In comparison, M. indicus plants cultivated in the presence of NaCl accumulated much less Na(+) in leaves and roots and no differences in K(+) content among plants grown in nutrient solution containing 100-400 mM NaCl were detected. The expression levels of four genes coding for NHX-type Na(+)/H(+) antiporters in the above two wild legumes were studied in plants cultivated under the different NaCl concentrations. Expression levels of the genes were higher in M. intertexta as compared with M. indicus plants. In M. intertexta, salt treatments increased MtNHX1, MtNHX3 and MtNHX4 transcript levels in leaves and roots. However, in M. indicus NaCl treatments only induced the expression of MtNHX1 in roots. Our data suggest that two different mechanisms, Na(+) avoidance or accumulation into cellular compartments, are developed by the two wild legumes to cope with salt stress, and that expression of NHX antiporters is linked to the accumulator phenotype.

A novel intracellular K+/H+ antiporter related to Na+/H+ antiporters is important for K+ ion homeostasis in plants.

In this study we have identified the first plant K+/H+ exchanger, LeNHX2 from tomato (Lycopersicon esculentum Mill. cv. Moneymaker), which is a member of the intracellular NHX exchanger protein family. The LeNHX2 protein, belonging to a subfamily of plant NHX proteins closely related to the yeast NHX1 protein, is abundant in roots and stems and is induced in leaves by short term salt or abscisic acid treatment. LeNHX2 complements the salt- and hygromycin-sensitive phenotype caused by NHX1 gene disruption in yeast, but affects accumulation of K+ and not Na+ in intracellular compartments. The LeNHX2 protein co-localizes with Prevacuolar and Golgi markers in a linear sucrose gradient in both yeast and plants. A histidine-tagged version of this protein could be purified and was shown to catalyze K+/H+ exchange but only minor Na+/H+ exchange in vitro. These data indicate that proper functioning of the endomembrane system relies on the regulation of K+ and H+ homeostasis by K+/H+ exchangers.