Transport of calcium across caco-2 cells in the presence of inositol hexakisphosphate

Unraveling the potential of bacterial phytases for sustainable management of phosphorous

Phosphorous actively participates in numerous metabolic and regulatory activities of almost all living organisms including animals and humans. Therefore, it is considered as an essential macronutrient required supporting their proper growth. On contrary, phytic acid (PA), an antinutritional substance, is widely known for its strong affinity to chelate essential mineral ions including PO4 3- , Ca2+ , Fe2+ , Mg2+ , and Zn2+ . Being one the major reservoir of PO4 3- ions, PA has great potential to bind PO4 3- ions in diverse range of foods. Once combined with P, PA transforms into an undigested and insoluble complex namely phytate. Produced phytate leads to a notable reduction in the bioavailability of P due to negligible activity of phytases in monogastric animals and humans. This highlights the importance and consequent need of enhancement of phytase level in these life forms. Interestingly, phytases, catalyzing the breakdown of phytate complex and recycling the phosphate into ecosystem to its available form, have naturally been reported in a variety of plants and microorganisms over past few decades. In pursuit of a reliable solution, the focus of this review is to explore the keynote potential of bacterial phytases for sustainable management of phosphorous via efficient utilization of soil phytate. The core of the review covers detailed discussion on bacterial phytases along with their widely reported applications viz. biofertilizers, phosphorus acquisition, and plant growth promotion. Moreover, meticulous description on fermentation-based strategies and future trends on bacterial phytases have also been included.

NM, Jebakani K. S, Selvaraj S, Pramitha J. L, Selvaraj R, Petchiammal K. I, Kather Sheriff S, Thinakaran J, Rathinamoorthy S, Kumar P. R. Genetic manipulation of anti-nutritional factors in major crops for a sustainable diet in future

The consumption of healthy food, in order to strengthen the immune system, is now a major focus of people worldwide and is essential to tackle the emerging pandemic concerns. Moreover, research in this area paves the way for diversification of human diets by incorporating underutilized crops which are highly nutritious and climate-resilient in nature. However, although the consumption of healthy foods increases nutritional uptake, the bioavailability of nutrients and their absorption from foods also play an essential role in curbing malnutrition in developing countries. This has led to a focus on anti-nutrients that interfere with the digestion and absorption of nutrients and proteins from foods. Anti-nutritional factors in crops, such as phytic acid, gossypol, goitrogens, glucosinolates, lectins, oxalic acid, saponins, raffinose, tannins, enzyme inhibitors, alkaloids, β-N-oxalyl amino alanine (BOAA), and hydrogen cyanide (HCN), are synthesized in crop metabolic pathways and are interconnected with other essential growth regulation factors. Hence, breeding with the aim of completely eliminating anti-nutrition factors tends to compromise desirable features such as yield and seed size. However, advanced techniques, such as integrated multi-omics, RNAi, gene editing, and genomics-assisted breeding, aim to breed crops in which negative traits are minimized and to provide new strategies to handle these traits in crop improvement programs. There is also a need to emphasize individual crop-based approaches in upcoming research programs to achieve smart foods with minimum constraints in future. This review focuses on progress in molecular breeding and prospects for additional approaches to improve nutrient bioavailability in major crops.

Safety of pea and rice protein fermented by Shiitake (Lentinula edodes) mycelia as a Novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on pea and rice protein fermented by Shiitake mushroom (Lentinula edodes) mycelia as a novel food (NF) pursuant to Regulation (EU) 2015/2283. The NF is a mixture of fermented pea and rice protein concentrates (65% and 35%, respectively). The NF is proposed to be used as a food ingredient in specific food categories. The target population is the general population. The major constituent of this NF is protein (≥ 75% dry weight), which is well digestible and provides sufficient amounts of essential amino acids. Although a tolerable upper intake level (UL) has not been derived for protein, the protein intake from the NF may nevertheless further contribute to an already high dietary protein intake in Europe. The Panel notes that the cumulative exposure to the nutrients and contaminants analysed does not raise concern. The reported values for the levels of antinutritional factors in the NF are comparable to those in other foodstuffs. The Panel considers that taking into account the composition of the NF and the proposed conditions of use, consumption of the NF is not nutritionally disadvantageous. No toxicological studies with the NF were provided by the applicant; however, the Panel considers that no toxicological studies are required for this NF. The NF has the potential capacity to sensitise individuals or to induce allergic reactions in individuals allergic to pea, rice and Shiitake mushroom. However, this risk is expected not to be higher than that resulting from the normal consumption of pea, rice or the fruiting body of the Shiitake mushroom. The Panel considers that the NF is safe at the proposed conditions of use.

Thermo-resistant enzyme-producing microorganisms isolated from composting

Organo-mineral fertilizers supplemented with biological additives are an alternative to chemical fertilizers. In this study, thermoresistant microorganisms from composting mass were isolated by two-step procedures. First, samples taken at different time points and temperatures (33 days at 52 ºC, 60 days at 63 ºC, and over 365 days at 26 ºC) were pre-incubated at 80 oC for 30 minutes. Second, the microbial selection by in vitro culture-based methods and heat shock at 60 oC and 100 oC for 2h and 4h. Forty-one isolates were able to grow at 60 °C for 4h; twenty-seven at 100 °C for 2h, and two at 100 °C for 4h. The molecular identification by partial sequencing of the 16S ribosomal gene using universal primers revealed that thirty-five isolates were from eight Bacillus species, one Brevibacillus borstelensis, three Streptomyces thermogriseus, and two fungi (Thermomyces lanuginosus and T. dupontii). Data from amylase, phytase, and cellulase activity assays and the enzymatic index (EI) showed that 38 of 41 thermo-resistant isolates produce at least one enzyme. For amylase activity, the highest EI value was observed in Bacillus licheniformis (isolate 21C2, EI= 4.11), followed by Brevibacillus borstelensis (isolate 6C2, EI= 3.66), Bacillus cereus (isolate 18C2, EI= 3.52), and Bacillus paralicheniformis (isolate 20C2, EI= 3.34). For phytase, the highest EI values were observed for Bacillus cereus (isolate 18C2, EI= 2.30) and Bacillus licheniformis (isolate 3C1, EI= 2.15). Concerning cellulose production, B. altitudinis (isolate 6C1) was the most efficient (EI= 6.40), followed by three Bacillus subtilis (isolates 9C1, 16C2, and 19C2) with EI values of 5.66, 5.84, and 5.88, respectively, and one B. pumilus (isolate 27C2, EI= 5.78). The selected microorganisms are potentially useful as a biological additive in organo-mineral fertilizers and other biotechnological processes.

Low phytic acid Crops: Observations Based On Four Decades of Research

The low phytic acid (lpa), or "low-phytate" seed trait can provide numerous potential benefits to the nutritional quality of foods and feeds and to the sustainability of agricultural production. Major benefits include enhanced phosphorus (P) management contributing to enhanced sustainability in non-ruminant (poultry, swine, and fish) production; reduced environmental impact due to reduced waste P in non-ruminant production; enhanced "global" bioavailability of minerals (iron, zinc, calcium, magnesium) for both humans and non-ruminant animals; enhancement of animal health, productivity and the quality of animal products; development of "low seed total P" crops which also can enhance management of P in agricultural production and contribute to its sustainability. Evaluations of this trait by industry and by advocates of biofortification via breeding for enhanced mineral density have been too short term and too narrowly focused. Arguments against breeding for the low-phytate trait overstate the negatives such as potentially reduced yields and field performance or possible reductions in phytic acid's health benefits. Progress in breeding or genetically-engineering high-yielding stress-tolerant low-phytate crops continues. Perhaps due to the potential benefits of the low-phytate trait, the challenge of developing high-yielding, stress-tolerant low-phytate crops has become something of a holy grail for crop genetic engineering. While there are widely available and efficacious alternative approaches to deal with the problems posed by seed-derived dietary phytic acid, such as use of the enzyme phytase as a feed additive, or biofortification breeding, if there were an interest in developing low-phytate crops with good field performance and good seed quality, it could be accomplished given adequate time and support. Even with a moderate reduction in yield, in light of the numerous benefits of low-phytate types as human foods or animal feeds, should one not grow a nutritionally-enhanced crop variant that perhaps has 5% to 10% less yield than a standard variant but one that is substantially more nutritious? Such crops would be a benefit to human nutrition especially in populations at risk for iron and zinc deficiency, and a benefit to the sustainability of agricultural production.

Reduction of phytic acid and enhancement of bioavailable micronutrients in food grains

More than half of the world populations are affected by micronutrient malnutrition and one third of world's population suffers from anemia and zinc deficiency, particularly in developing countries. Iron and zinc deficiencies are the major health problems worldwide. Phytic acid is the major storage form of phosphorous in cereals, legumes, oil seeds and nuts. Phytic acid is known as a food inhibitor which chelates micronutrient and prevents it to be bioavailabe for monogastric animals, including humans, because they lack enzyme phytase in their digestive tract. Several methods have been developed to reduce the phytic acid content in food and improve the nutritional value of cereal which becomes poor due to such antinutrient. These include genetic improvement as well as several pre-treatment methods such as fermentation, soaking, germination and enzymatic treatment of grains with phytase enzyme. Biofortification of staple crops using modern biotechnological techniques can potentially help in alleviating malnutrition in developing countries.

Effect of dephytinization on bioavailability of iron, calcium and zinc from infant cereals assessed in the Caco-2 cell model

AIM: To test the effect of the dephytinization of three different commercial infant cereals on iron, calcium, and zinc bioavailability by estimating the uptake, retention, and transport by Caco-2 cells.

METHODS: Both dephytinized (by adding an exogenous phytase) and non-dephytinized infant cereals were digested using an in vitro digestion protocol adapted to the gastrointestinal conditions of infants younger than 6 mo. Mineral cell retention, transport, and uptake from infant cereals were measured using the soluble fraction of the simulated digestion and the Caco-2 cells.

RESULTS: Dephytinization of infant cereals significantly increased (P < 0.05) the cell uptake efficiency (from 0.66%-6.05% to 3.93%-13%), retention (from 6.04%-16.68% to 14.75%-20.14%) and transport efficiency (from 0.14%-2.21% to 1.47%-6.02%), of iron, and the uptake efficiency (from 5.0%-35.4% to 7.3%-41.6%) and retention (from 4.05%-20.53% to 14.45%-61.3%) of zinc, whereas calcium only cell uptake showed a significant increase (P < 0.05) after removing phytate from most of the samples analyzed. A positive relationship (P < 0.05) between mineral solubility and the cell uptake and transport efficiencies was observed.

CONCLUSION: Removing phytate from infant cereals had a beneficial effect on iron and zinc bioavailability when infant cereals were reconstituted with water. Since in developing countries cereal-based complementary foods for infants are usually consumed mixed with water, exogenous phytase additions could improve the nutritional value of this weaning food.

Phytate: impact on environment and human nutrition. A challenge for molecular breeding

Phytic acid (PA) is the primary storage compound of phosphorus in seeds accounting for up to 80% of the total seed phosphorus and contributing as much as 1.5% to the seed dry weight. The negatively charged phosphate in PA strongly binds to metallic cations of Ca, Fe, K, Mg, Mn and Zn making them insoluble and thus unavailable as nutritional factors. Phytate mainly accumulates in protein storage vacuoles as globoids, predominantly located in the aleurone layer (wheat, barley and rice) or in the embryo (maize). During germination, phytate is hydrolysed by endogenous phytase(s) and other phosphatases to release phosphate, inositol and micronutrients to support the emerging seedling. PA and its derivatives are also implicated in RNA export, DNA repair, signalling, endocytosis and cell vesicular trafficking. Our recent studies on purification of phytate globoids, their mineral composition and dephytinization by wheat phytase will be discussed. Biochemical data for purified and characterized phytases isolated from more than 23 plant species are presented, the dephosphorylation pathways of phytic acid by different classes of phytases are compared, and the application of phytase in food and feed is discussed.