Bulgur processes increase nutrition value: possible role in in-vitro protein digestability, phytic acid, trypsin inhibitor activity and mineral bioavailability

Kinetics of chemical and color changes in wheat and water during atmospheric cooking as affected by the acidity, hardness, and iron content of water

Color changes in wheat and cooking water, which affect the quality of bulgur and wastewater, are important. Understanding the impacts of cooking water acidity, hardness, and iron content is significant for producing bright-yellow colored bulgur and determining the possible negative effects of cooking water on the environment. Thereby, the gelatinization degree and color (L*, a*, b*, and yellowness index) of wheat cooked with waters at different pH (3, 5, 7, 9, and 11), hardness (soft, hard, and very hard), and iron content (0, 1, and 2 mg/L) were determined every 10 min of cooking. pH, Brix, conductivity, hardness, turbidity, and color of cooking waters were also determined and kinetically modeled. After cooking, it was revealed that cooking with water at pH 3 favored the color of cooked wheat, whereas pH 11 caused darkening. Nevertheless, as the wastewater pH of cooking waters with pH 3 and 11 may be harmful to the environment, it is recommended to use water in the range of pH 5-9 for bulgur production. Cooking with very hard water is also not recommended as it causes some adverse effects such as diminishing the gelatinization rate in wheat, increasing the cooking time, and negatively affecting the color.

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.

Drying Behavior of Bulgur and Its Effect on Phytochemical Content

The objective of this study was to determine the influence of two types of dryers (hot air oven and vacuum dryer) and the yellow berry percentage (1.75%, 36.25%, 43.25%) on the drying process and phytochemical content of bulgur. Results showed that the Midilli model successfully described the moisture diffusion during drying at 60 °C in all bulgur samples, where an increase in yellow berry percentage generated an increase in moisture content. Effective diffusion coefficient (Deff) increased significantly (p ≤ 0.05) from 7.05 × 10−11 to 7.82 × 10−11 (m2.s−1) and from 7.73 × 10−11 to 7.82 × 10−11 (m2.s−1) for the hot air oven and vacuum dryer, respectively. However, it decreased significantly with a decrease of yellow berry percentage. It was concluded that the vacuum dryer provided faster and more effective drying than the hot air oven. Total polyphenol (TPC), total flavonoid (TFC), and yellow pigment contents (YPC) of bulgur were investigated. TPC ranged between 0.54 and 0.64 (mg GAE/g dm); TFC varied from 0.48 to 0.61 (mg QE/g dm). The YPC was found to be between 0.066 and 0.079 (mg ß-carotene/100g dm). Yellow berry percentage positively and significantly affected the TPC, TFC, and YPC contents due to the hard separation of the outer layers from the starchy grain during the debranning step.

Pulse-based snacks as functional foods: Processing challenges and biological potential

Despite their high nutritional value and potential health benefits, pulse intake has not increased in the last three decades. Several strategies have been implemented to increase pulse consumption, such as their incorporation in bakery products, breakfast cereals, and snacks. The inclusion of pulses in these products could be an alternative to satisfy the consumers' demand for healthy foods. However, pulse-based snacks face important challenges, including reducing antinutritional factors, achieving consumer acceptance, and consolidating the pulse-based snacks as functional foods. This review summarizes and discusses methods for producing snacks where cereals or tubers were replaced with at least 50% pulses. Also, it briefly assesses their effect on nutritional composition, antinutritional factors, sensory acceptance, and different health benefits evaluations. Extruded snacks exhibited high protein and dietary fiber and low fat content, contrary to the high fat content of deep fat-fried snacks. Meanwhile, baked snacks presented moderate concentrations of protein, dietary fiber, and lipids. Pulses must be pretreated using process combinations such as soaking, dehulling, cooking, fermentation, germination, and extrusion to reduce the antinutritional factors. Pulse-based snacks show good sensory acceptance. However, sensory evaluation should be more rigorous using additional untrained judges. Several studies have evaluated the health benefits of pulse-based snacks. More research is needed to validate scientifically the health benefits associated with their consumption. Pulse-based snacks could be an alternative to improve the nutritional composition of commercially available snacks. The use of pulses as ingredients of healthier snacks represents an important alternative for the food industry due to their low cost, sensory characteristics, high nutritional profile, and environmental benefits.

The Effect of Processing on Bioactive Compounds and Nutritional Qualities of Pulses in Meeting the Sustainable Development Goal 2

Diversification of plant-based food sources is necessary to improve global food and nutritional security. Pulses have enormous nutritional and health benefits in preventing malnutrition and chronic diseases while contributing positively to reducing environmental footprint. Pulses are rich in diverse nutritional and non-nutritional constituents which can be classified as bioactive compounds due to their biological effect. These bioactive compounds include but are not limited to proteins, dietary fibres, resistant starch, polyphenols, saponins, lectins, phytic acids, and enzyme inhibitors. While these compounds are of importance in ensuring food and nutritional security, some of the bioactive constituents have ambivalent properties. These properties include having antioxidant, anti-hypertensive and prebiotic effects. Others have a deleterious effect of decreasing the digestibility and/or bioavailability of essential nutrients and are therefore termed antinutritional factors/compounds. Various processing techniques exist to reduce the content of antinutritional factors found in pulses. Traditional processing of pulses comprises soaking, dehulling, milling, germination, fermentation, and boiling, while examples of emerging processing techniques include microwaving, extrusion, and micronization. These processing techniques can be tailored to purpose and pulse type to achieve desired results. Herein, the nutritional qualities and properties of bioactive compounds found in pulses in meeting the sustainable development goals are presented. It also discusses the effect of processing techniques on the nutritional and non-nutritional constituents in pulses as well as the health and environmental benefits of pulse-diet consumption. Major challenges linked to pulses that could limit their potential of being ideal crops in meeting the sustainable development goal 2 agenda are highlighted.

Phytic acid: Blessing in disguise, a prime compound required for both plant and human nutrition

Phytic acid (PA), [myo-inositol 1,2,3,4,5,6-hexakisphosphate] is the principal storage compound of phosphorus (P) and account for 65%-85% of the seeds total P. The negative charge on PA attracts and chelates metal cations resulting in a mixed insoluble salt, phytate. Phytate contains six negatively charged ions, chelates divalent cations such as Fe2+, Zn2+, Mg2+, and Ca2+ rendering them unavailable for absorption by monogastric animals. This may lead to micronutrient deficiencies in humans since they lack the enzyme phytase that hydrolyzes phytate and releases the bound micronutrients. There are two main concerns about the presence of PA in human diet. The first is its negative impact on the bioavailability of several minerals and the second is the evidence of PA inhibiting various proteases essential for protein degradation and the subsequent digestion in stomach and small intestine. The beneficial role of PA has been underestimated due to its distinct negative consequences. PA is reported to be a potent natural plant antioxidant which plays a protective role against oxidative stress in seeds and preventive role in various human diseases. Recently beneficial roles of PA as an antidiabetic and antibacterial agent has been reported. Thus, the development of grains with low-PA and modified distribution pattern can be achieved through fine-tuning of its content in the seeds.

Plant food anti-nutritional factors and their reduction strategies: an overview

Abstract

Legumes and cereals contain high amounts of macronutrients and micronutrients but also anti-nutritional factors. Major anti-nutritional factors, which are found in edible crops include saponins, tannins, phytic acid, gossypol, lectins, protease inhibitors, amylase inhibitor, and goitrogens. Anti-nutritional factors combine with nutrients and act as the major concern because of reduced nutrient bioavailability. Various other factors like trypsin inhibitors and phytates, which are present mainly in legumes and cereals, reduce the digestibility of proteins and mineral absorption. Anti-nutrients are one of the key factors, which reduce the bioavailability of various components of the cereals and legumes. These factors can cause micronutrient malnutrition and mineral deficiencies. There are various traditional methods and technologies, which can be used to reduce the levels of these anti-nutrient factors. Several processing techniques and methods such as fermentation, germination, debranning, autoclaving, soaking etc. are used to reduce the anti-nutrient contents in foods. By using various methods alone or in combinations, it is possible to reduce the level of anti-nutrients in foods. This review is focused on different types of anti-nutrients, and possible processing methods that can be used to reduce the level of these factors in food products.

Graphical abstract

A brief overview of beneficial effects of anti-nutrients and reduction strategy.

Manipulating the Phytic Acid Content of Rice Grain Toward Improving Micronutrient Bioavailability

Myo-inositol hexaphosphate, also known as phytic acid (PA), is the most abundant storage form of phosphorus in seeds. PA acts as a strong chelator of metal cations to form phytate and is considered an anti-nutrient as it reduces the bioavailability of important micronutrients. Although the major nutrient source for more than one-half of the global population, rice is a poor source of essential micronutrients. Therefore, biofortification and reducing the PA content of rice have arisen as new strategies for increasing micronutrient bioavailability in rice. Furthermore, global climate change effects, particularly rising atmospheric carbon dioxide concentration, are expected to increase the PA content and reduce the concentrations of most of the essential micronutrients in rice grain. Several genes involved in PA biosynthesis have been identified and characterized in rice. Proper understanding of the genes related to PA accumulation during seed development and creating the means to suppress the expression of these genes should provide a foundation for manipulating the PA content in rice grain. Low-PA rice mutants have been developed that have a significantly lower grain PA content, but these mutants also had reduced yields and poor agronomic performance, traits that challenge their effective use in breeding programs. Nevertheless, transgenic technology has been effective in developing low-PA rice without hampering plant growth or seed development. Moreover, manipulating the micronutrient distribution in rice grain, enhancing micronutrient levels and reducing the PA content in endosperm are possible strategies for increasing mineral bioavailability. Therefore, a holistic breeding approach is essential for developing successful low-PA rice lines. In this review, we focus on the key determinants for PA concentration in rice grain and discuss the possible molecular methods and approaches for manipulating the PA content to increase micronutrient bioavailability.

The effect of ultrasound on some properties of pulse hulls

The aim of this study was to understand the effects of different ultrasound conditions on dietary fiber, phytic acid, total phenolics content, water and oil binding capacity, antioxidant capacity and phenolic acid composition of hull from green and red lentils (Lens culinaris), faba bean (Vicia faba), and pea (Pisum sativum). The highest and the lowest total dietary fiber content was observed in red lentil and faba bean hulls, respectively. Insoluble dietary fiber contents of the untreated pulse hulls were above 66% regardless of the pulse type. Phytic acid content of the pulse hulls ranged between 1.37 and 1.66 mg/g and was not affected from either the pulse type or ultrasound treatment. High and significant correlations were found between total phenolics content and Trolox equivalent antioxidant capacity both of which showed higher values for lentil hulls. Bound (hydrolyzable) extracts contained higher amounts of phenolic acids compared to free form extracts. Protocathechuic, p-coumaric and ferulic acids either in free or bound (hydrolyzable) form were present in hull from all the pulses. Ultrasound treated samples showed significantly lower total phenolic content and TEAC values compared to control for lentil hulls, while no consistent trend was observed for phenolic acids with regard to the ultrasound conditions.

Interaction of phenolic acids with trypsin: Experimental and molecular modeling studies

Trypsin is a kind of protease for digestion and food processing, whose activity can be inhibited by phenolic acids in plant foods. However, most reports explained the inhibitory difference of phenolic acids based on the number and position of substituent groups, which failed to reveal the comprehensive inhibitory mechanism. In this work, the inhibitory effects of 11 common phenolic acids on trypsin were investigated. Amongst the tested cinnamic and benzoic acid derivatives, caffeic acid and gallic acid showed the strongest anti-trypsin activity with a noncompetitive inhibition pattern, respectively. The fluorescence analysis displayed that both the quenching rate constant (K_q) and binding constant (K_A) of caffeic acid were higher than those of gallic acid. Molecular docking illustrated their different binding modes with trypsin. The ONIOM calculations revealed that the binding capacity of caffeic acid was higher than that of gallic acid, which could explain their difference in their inhibitory behaviors.

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 different debittering processes on mineral and phytic acid content of lupin (Lupinus albus L.) seeds

Lupin is a valuable ancient legume which contains high amount of protein, dietary fiber, oil, minerals and different functional components. Bitter lupin seeds cannot be consumed directly since its high toxic alkaloid content. Cooking and soaking are effective processes for removing these toxic substances and antinutrients as phytic acid, trypsin inhibitors and oligosaccharides. In this study, debittering process containing cooking and soaking up to 144 h was applied to lupin seeds. Raw lupin seeds had 3.3 % ash and 41.3 % protein content. Ash and protein content of debittered seeds changed between 2.1 and 2.5 %, 39.5 and 40.9 % respectively. After debittering process, significant (p < 0.05) decreases (between % 5.7 and 75.7) were observed in calcium, phosphorus, zinc, iron, magnesium and manganese contents of the lupin seeds. Phytic acid was removed from raw lupin seeds up to 71.4 % ratio by debittering processes, and soaking in distilled water at 55 °C and long soaking time (144 h) was found the most effective methods on phytic acid loss. While more lighter (L*) seeds were obtained with soaking in distilled water at 25 °C, soaking in 0.5 % NaHCO3 solution gave more yellowish (b*) seed properties compared to other soaking methods. Soaking in 0.5 % NaHCO3 solution at 144 h gave the most liked products in terms of sensorial evaluation.

Effect of fermentation on antinutrients, and total and extractable minerals of high and low phytate corn genotypes

Two corn genotypes, Var-113 (high phytate) and TL-98B-6225-9×TL617 (low phytate) were fermented for 14 days. The fermented flour was dried and milled. Phytic acid and polyphenols contents and hydrochloric acid (HCl) extractability of minerals from the fermented flours were determined at intervals of 2 days during fermentation period. Phytic acid and polyphenols decreased significantly (P ≤ 0.05) with an increase in fermentation period, with a concomitant increase in HCl extractable minerals. For both genotypes the major and trace minerals content was increased with fermentation period. When the grains flour was fermented for 14 days, TL-98B-6225-9×TL617 genotype had higher extractable calcium (94.73 %) while Var-113 had higher extractable phosphorus (76.55 %), whereas iron recorded high extractability levels (84.93 %) in TL-98B-6225-9×TL617 and manganese recorded high extractability levels (81.07 %) in Var-113. There was good correlation between phytate and polyphenols levels reduction and the increment in extractable minerals with fermentation period.