The influence of inoculum composition on selected bioactive and nutritional parameters of grass pea tempeh obtained by mixed-culture fermentation with Rhizopus oligosporus and Aspergillus oryzae strains

The importance and mitigation of mycotoxins and plant toxins in Southeast Asian fermented foods

Fermented foods (ffs) and beverages are widely consumed in Southeast Asia (SEA) for their nutritional balance, flavor, and food security. They serve as vehicles for beneficial microorganisms performing a significant role in human health. However, there are still major challenges concerning the safety of ffs and beverages due to the presence of natural toxins. In this review, the common toxins found in traditional ffs in SEA are discussed with special reference to mycotoxins and plant toxins. Also, mitigation measures for preventing risks associated with their consumption are outlined. Ochratoxin, citrinin, aflatoxins were reported to be major mycotoxins present in SEA ffs. In addition, soybean-based ff food products were more vulnerable to mycotoxin contaminations. Common plant toxins recorded in ffs include cyanogenic glycosides, oxalates, phytates and saponins. Combined management strategies such as pre-harvest, harvest and post-harvest control and decontamination, through the integration of different control methods such as the use of clean seeds, biological control methods, fermentation, appropriate packaging systems, and controlled processing conditions are needed for the safe consumption of indigenous ffs in SEA.

Tempeh: A semicentennial review on its health benefits, fermentation, safety, processing, sustainability, and affordability

Tempeh is a fermented food made of mainly soybeans and is a nutritious, affordable, and sustainable functional source of protein. Globally, tempeh is a widely accepted fermented product. Although there is a growing body of literature on tempeh, most research has focused on unfermented soybeans, thus the impact of tempeh fermentation on biological properties of soybeans has been largely left scattered. The objective of this review is to summarize the literature of tempeh fermentation over the past 60 years. A search of articles on tempeh published from 1960 to 2020 was performed using the Cochrane Library, Web of Science, EBSCOhost FSTA database, and Google Scholar. References from identified articles were reviewed for additional sources. In total, 321 papers were selected for this review, of which 64 papers were related to the health benefits of tempeh. This review concluded that sufficient evidence exists in the literature supporting tempeh fermentation as a low-cost, health-promoting, and sustainable food processing technology to produce protein-rich foods using various beans, legumes, and grains. This comprehensive review suggests further studies are needed on tempeh fermentation and its impact on human health; research and standardization of nonsoy tempeh; assessment of food safety-improving modification in tempeh production system; and initiatives supporting the sourcing of local ingredients in tempeh production.

Profile and bioavailability analysis of myo-inositol phosphates in rye bread supplemented with phytases: a study using an in vitro method and Caco-2 monolayers

Commercial preparations of 6-phytase A alone and in combination with phytase B were used in rye breadmaking. Determination of bioavailability of myo-inositol phosphates from bread was performed by an in vitro digestion method followed by the measurement of an uptake by Caco-2 cells in culture. In bread supplemented with a combination of 6-phytase A and phytase B, a significant reduction in phytate content was observed from 3.62 μmol/g in the control to 0.7 μmol/g. Bioavailability of phytate estimated by an in vitro method simulating digestion in the human alimentary tract was 9% in the bread supplemented with phytase B, 7% (6-phytase A) and 50% in the control bread. In cell culture, the bioaccessibilities of inositol triphosphates from bread baked with the addition of 6-phytase A was higher by 36% as compared to the samples baked with phytase B and by 32% in breads baked with combination of both phytases.

Phytases Improve Myo-Inositol Bioaccessibility in Rye Bread: A Study Using an In Vitro Method of Digestion and a Caco-2 Cell Culture Model

Preparations of 6-phytase A (EC 3.1.3.26) and phytase B (acid phosphatase, EC 3.1.3.2) were applied alone and combined in the preparation of dough to estimate their catalytic potential for myo-inositol liberation from rye flour in the breadmaking technology. The experimental bread samples were ground after baking and subjected to determination of myo-inositol bioavailability by an in vitro method that simulated digestion in a human alimentary tract, followed by measurements of myo-inositol transport through enterocyte- -like differentiated Caco-2 cells to determine its bioaccessibility. Myo-inositol content was measured by a high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) technique. The concentration of myo-inositol in the dialysates of control bread was 25.3 µg/mL, whereas in the dialysates of bread sample baked with 6-phytase A, the concentration increased to 35.4 µg/mL, and in the bread baked with phytase B to 64.98 µg/mL. Simultaneous application of both enzymes resulted in myo-inositol release of 64.04 µg/mL. The highest bioaccessibility of myo-inositol, assessed by the measurement of the passage through the Caco-2 monolayer was determined in the bread baked with the addition of 6-phytase A. Enzymatically modified rye bread, particularly by the addition of 6-phytase A, may be therefore a rich source of a highly bioaccessible myo- -inositol.

Effect of controlled lactic acid fermentation on selected bioactive and nutritional parameters of tempeh obtained from unhulled common bean (Phaseolus vulgaris) seeds

BACKGROUND

Tempeh is a traditional Indonesian food of high nutritional quality obtained by fungal fermentation of dehulled, soaked and cooked legumes. The aim of this research was to study the effect of Lactobacillus plantarum DSM 20174 activity on selected parameters of tempeh made from unhulled seeds of common bean (Phaseolus vulgaris). Lactobacillus plantarum cells were applied during soaking of seeds (submerged fermentation) or during solid state fermentation with Rhizopus microsporus var. chinensis (co-cultivation).

RESULTS

Tempeh obtained from common beans contained 200 g kg⁻¹ protein of 34% in vitro bioavailability. Fungal fermentation caused decomposition of raffinose, stachyose and verbascose levels in seeds, on average by 93, 84 and 73% respectively. Enhanced antiradical (DPPH•, ABTS•+) capacity was accompanied by increased soluble phenol content. Application of Lactobacillus in the fermentation procedure increased tempeh protein and in vitro protein bioavailability by 18 and 17% respectively. Mixed culture tempeh contained lower levels of stachyose (25%), verbascose (64%) and condensed tannins (20%). Co-cultivation enhanced both DPPH•-scavenging activity and antioxidant capacity.

CONCLUSION

The application of Lactobacillus in most cases improved the nutritional parameters of tempeh from unhulled common beans. It may also be recommended to obtain products with diverse antioxidant properties as compared with fungal fermentation alone.