Pulse proteins: Processing,characterization, functional properties and applications in food and feed

Pulses (pea, chickpea, lentil, bean) are an important source of food proteins. They contain high amounts of lysine, leucine, aspartic acid, glutamic acid and arginine and provide well balanced essential amino acid profiles when consumed with cereals and other foods rich in sulphur-containing amino acids and tryptophan. The protein content of most pulse legumes fall within the range of 17–30% (d.w.b.). Apart from their nutritional properties, pulse proteins also possess functional properties that play an important role in food formulation and processing. Examples of such functional properties include solubility, water and fat binding capacity and foaming. Various research studies indicate that some functional properties of pulse proteins may be comparable to those of other frequently used proteins such as soy and whey. The functional properties of pulse proteins have been exploited in the preparation and development of products such as bakery products, soups, extruded products and ready to eat snacks. The growing body of research on the health benefits associated with the consumption of pulses has increased interest in developing innovative technologies to expand the use of pulses in food products. At the same time, there are growing global food security challenges and protein malnutrition continues to be a problem in many countries around the world. Pulses, especially when blended with cereal proteins, may offer a promising alternative source for nutritional and functional proteins. This review provides an overview of the characteristics of pulse proteins, current and emerging techniques for their fractionation, their major functional properties and opportunities for their use in various applications.     

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.     

Seed coats of pulses as a food ingredient: Characterization,processing, and applications

BackgroundIn recognition of their multiple benefits on environment, food security, and human health, pulses are attracting worldwide attention. The seed coat is a major by-product of pulse processing, and its only markets are as low value ruminant feed and very limited use in high fibre foods. Recently, accumulating studies have suggested that this underutilised by-product has greater potential as a novel natural “nutritious dietary fibre” which can be used as a functional food ingredient.Scope and approachThis review discusses biochemical and physicochemical functionalities of seed coats of six globally important pulses: chickpea, field pea, faba/broad bean, lentil and mung bean with a special emphasis on the emerging food pulse lupin. Food process modification and recent human food applications of the seed coats are summarized. Bio-availability of the seed coat compounds, and phomopsins contaminated lupin seed coats as a typical example of safety issue are discussed.Key findings and conclusionsHigh levels of dietary fibre, minerals and potential health-promoting phytochemicals in the seed coats indicate their great potential to be used as a natural “nutritious dietary fibre”. However, further in-depth studies are required to improve their desirable nutritional, physiological and techno-functional properties whilst minimizing any undesirable ones.     

Suitability,efficiency and microbiological safety of novel physical technologies for the processing of ready‐to‐eat meals,meats and pumpable products

Consumer studies and market reports show an increase in consumption of ready‐to‐eat (RTE) foods. Although conventional processing technologies can in most cases produce safe products, they can also lead to the degradation of nutritional compounds and negatively affect quality characteristics. Consumers strongly prefer food that is minimally processed with the maximum amount of health‐promoting substances. Novel processing technologies as pre‐ or post‐treatment decontamination methods or as substitutes of conventional technologies have the potential to produce foods that are safe, rich in nutrient content and with superior organoleptic properties. Combining novel with conventional processes can eliminate potential drawbacks of novel technologies. This review examines available scientific information and critically evaluates the suitability and efficiency of various novel thermal and nonthermal technologies in terms of microbial safety, quality as well as nutrient content on the production of RTE meals, meats and pumpable products.     

An updated review of dietary isoflavones: Nutrition,processing, bioavailability and impacts on human health

Isoflavones (genistein, daidzein, and glycitein) are bioactive compounds with mildly estrogenic properties and often referred to as phytoestrogen. These are present in significant quantities (up to 4–5 mg·g^?1 on dry basis) in legumes mainly soybeans, green beans, mung beans. In grains (raw materials) they are present mostly as glycosides, which are poorly absorbed on consumption. Thus, soybeans are processed into various food products for digestibility, taste and bioavailability of nutrients and bioactives. Main processing steps include steaming, cooking, roasting, microbial fermentation that destroy protease inhibitors and also cleaves the glycoside bond to yield absorbable aglycone in the processed soy products, such as miso, natto, soy milk, tofu; and increase shelf lives. Processed soy food products have been an integral part of regular diets in many Asia–Pacific countries for centuries, e.g. China, Japan and Korea. However, in the last two decades, there have been concerted efforts to introduce soy products in western diets for their health benefits with some success. Isoflavones were hailed as magical natural component that attribute to prevent some major prevailing health concerns. Consumption of soy products have been linked to reduction in incidence or severity of chronic diseases such as cardiovascular, breast and prostate cancers, menopausal symptoms, bone loss, etc. Overall, consuming moderate amounts of traditionally prepared and minimally processed soy foods may offer modest health benefits while minimizing potential for any adverse health effects.     

Dietary fibres in pulse seeds and fractions: Characterization,functional attributes,and applications

Pulses are a good source of dietary fibre and other important nutrients. Flours and fibre-rich fractions obtained from pulse crops can be incorporated into processed foods to increase dietary fibre content and/or serve as functional ingredients. This review focuses on research conducted in the past ten years on the non-starch polysaccharides and oligosaccharides found in dry beans (Phaseolus vulgaris), chickpeas (Cicer arietinum), lentils (Lens culinaris), and dry peas (Pisum sativum). The isolation, composition, and structure of these pulse fibres are described. Common terms used to describe the physicochemical properties of fibre fractions are defined and briefly discussed. Recent studies on the effects of processing on the ratio of insoluble to soluble dietary fibre and on the α-galacto-oligosaccharide content of pulses and fibre fractions are cited and summarized. Food applications for pulse fibre fractions and flours in fibre enrichment, nutrient enrichment, fat binding and retention, and texture modification, as well as some non-food applications, are reviewed.     

Application and Opportunities of Pulses in Food System: A Review

Pulses are highly nutritious seeds of pod-bearing leguminous plants, specifically dry peas, lentils, and chickpeas. US farmers harvest about 2.6 million pounds of pulses every year but 75% of this is being exported internationally because of its increased consumption in the developing countries. In the current scenario, increasing costs of production, bad economy, and fluctuating food commodity prices have made a strong case for US producers to seek opportunities to increase domestic consumption of pulses through value-added products. Pulses are the richest sources of plant proteins and provide approximately 10% of the total dietary requirements of the proteins world over. Pulses are also high in dietary fibers and complex carbohydrates leading to low GI (glycemic index) foods. Pulses help to lower cholesterol and triglycerides as leguminous fibers are hypoglycosuria because of consisting more amylose than amylopectin. Pulses provide tremendous opportunities to be utilized in the processed foods such as bakery products, bread, pasta, snack foods, soups, cereal bar filing, tortillas, meat, etc. These show excellent opportunities in frozen dough foods either as added flour or as fillings. Pulses in view of their nutrient profile, seem to be ideal for inclusion in designing snack foods, baby, and sports foods.     

How postharvest variables in the pulse value chain affect nutrient digestibility and bioaccessibility

Pulses are increasingly being put forward as part of healthy diets because they are rich in protein, (slowly digestible) starch, dietary fiber, minerals, and vitamins. In pulses, nutrients are bioencapsulated by a cell wall, which mostly survives cooking followed by mechanical disintegration (e.g., mastication). In this review, we describe how different steps in the postharvest pulse value chain affect starch and protein digestion and the mineral bioaccessibility of pulses by influencing both their nutritional composition and structural integrity. Processing conditions that influence structural characteristics, and thus potentially the starch and protein digestive properties of (fresh and hard-to-cook [HTC]) pulses, have been reported in literature and are summarized in this review. The effect of thermal treatment on the pulse microstructure seems highly dependent on pulse type-specific cell wall properties and postharvest storage, which requires further investigation. In contrast to starch and protein digestion, the bioaccessibility of minerals is not dependent on the integrity of the pulse (cellular) tissue, but is affected by the presence of mineral antinutrients (chelators). Although pulses have a high overall mineral content, the presence of mineral antinutrients makes them rather poorly accessible for absorption. The negative effect of HTC on mineral bioaccessibility cannot be counteracted by thermal processing. This review also summarizes lessons learned on the use of pulses for the preparation of foods, from the traditional use of raw-milled pulse flours, to purified pulse ingredients (e.g., protein), to more innovative pulse ingredients in which cellular arrangement and bioencapsulation of macronutrients are (partially) preserved.     

Inactivation of bacillus subtilis by high intensity pulsed electric fields under close to isothermal conditions

Abstract

Because of expected nutritional, sensorical and health benefits, non‐thermal processing has the potential to satisfy the growing demand for minimally processed foods and can simultaneously provide safe and stable foods. Since the 60's the use of high intensity pulsed electric fields in food processing has repeatedly been demonstrated for e.g. pasteurization or cell permeabilization. The technical advance in the field of pulsed power equipment during the last years legitimates the approach of re‐considering some of these processes.

In this work the inactivation of vegetative Bacillus subtilis ATCC 9372 by high intensity pulsed electric fields was investigated in a batch treatment chamber. A switching system was used which allowed the application of square wave pulses with variable on‐time and a turn‐on rise time of less than 50 ns. Field strength from 2.5 to 52.8 kV/cm was investigated. The aim was to clearly discriminate between the effect of field strength and pulse energy without thermal interference.

It was found that inactivation is a linear function of field strength. A threshold field strength which has to be exceeded to achieve cell death was not observed. However, a minimum specific pulse energy was required to affect the micro‐organisms.     

Effect of storage on resistant starch and amylose content of cereal–pulse based ready-to-eat commercial products

A wide range of ready-to-eat (RTE) foods, with varied shelf life are commercially available to meet the increasing demand for convenience foods, both by the Armed Forces and the public at large. The study evaluated the effect of storage on the resistant starch (RS) and amylose content of selected ready-to-eat (RTE) cereal–pulse based processed foods viz., pongal, khara bhath, dal fry, bisibele bhath, rajmah and kesari bhath, developed by Defence Food Research Laboratory, Mysore. RS was quantified directly in the residues obtained after removing digested starch in simulated physiological conditions. Nutrient composition and carbohydrate profile of the foods were also analyzed. The carbohydrate profile indicated low amounts of sugars, except in case of kesari bhath. The total starch content ranged from 14.5 to 24 g% while amylose ranged from 1.2 to 7.2 g%, respectively. The total and resistant starch in the RTE foods varied depending on the ingredients used and type of processing. Foods containing higher amylose content were found to have maximum increases in RS content after storage. Storage at ambient conditions resulted in significant increases (p < 0.05) in RS and TS content of RTE foods. The findings reveal that the RTE foods studied hitherto contained appreciable quantities of RS, which further increased on storage.     

常见加工方式对杂豆品质的影响与调控

杂豆富含蛋白质、膳食纤维和维生素等多种营养成分，但也含有植酸、胰蛋白酶抑制剂、植物凝集素等抗营养因子，这大大降低了其生物利用率。采用不同的加工方法可以降低或去除抗营养因子，从而改善杂豆的营养品质、风味品质和感官特性，提升杂豆适用性。常见加工方式主要包括浸泡、脱壳、煮制、微波处理、高压处理、挤压膨化、烘烤、发酵和发芽等。本文总结不同加工方式对杂豆品质的影响，以期为精准调控杂豆品质和发展新型杂豆加工技术提供理论参考和新的研究方向。     

Microbiological safety of ready‐to‐eat foods in low‐ and middle‐income countries: A comprehensive 10‐year (2009 to 2018) review

Ready‐to‐eat foods (RTEs) are foods consumed without any further processing. They are widely consumed as choice meals especially by school‐aged children and the fast‐paced working class in most low‐ and middle‐income countries (LMICs), where they contribute substantially to the dietary intake. Depending on the type of processing and packaging material, RTEs could be industrially or traditionally processed. Typically, RTE vendors are of low literacy level, as such, they lack knowledge about good hygiene and food handling practices. In addition, RTEs are often vended in outdoor environments such that they are exposed to several contaminants of microbial origin. Depending on the quantity and type of food contaminant, consumption of contaminated RTEs may result in foodborne diseases and several other adverse health effects in humans. This could constitute major hurdles to growth and development in LMICs. Therefore, this review focuses on providing comprehensive and recent occurrence and impact data on the frequently encountered contaminants of microbial origin published in LMICs within the last decade (2009 to 2018). We have also suggested viable food safety solutions for preventing and controlling the food contamination and promoting consumer health.     

Food processing,gut microbiota and the globesity problem

Abstract

In the context of diseases of affluence, western diets have in the past years mainly been studied on their fat and sugar content and lack of dietary fiber. Yet, the more general aspect of food processing has recently sparked scientific interest as well. In addition, the gut microbiota have been put forward as an important link between diet, obesity and non-communicable diseases (NCD). Western dietary patterns, containing large amounts of processed foods might create an imbalance in the gut system by affecting gut bacteria and their metabolism. Here we discuss what has been already published regarding the relationship between several recently researched features of processed foods and the etiology of obesity and NCD. The addressed features concern micronutrient and energy density, several types of food additives and the generation of advanced glycation end products by thermal treatment during food processing. Overall, literature indicates that all discussed aspects can be linked to western ailments and that they can have a potential negative impact on human microbiota. Therefore, we propose that the thesis that a distressed gut microbiota is a mechanism that might explain how food processing features could harm human health is gaining empirical evidence. Future research will need to address the question whether the alteration of the gut microbiota is a direct or an indirect (via the host) effect. These conclusions are important assets in the fight against the continuing worldwide upsurge of obesity and NCD.     

Extracts of common pulses demonstrate potent in vitro anti‐adipogenic properties

Pulses are an important food source in many countries and also widely used as feed for livestock. Discovery of novel health benefits in pulses may contribute to improved diet and potential added value to crops. In this study, we examined the ability of extracts from faba bean, field pea and chickpea to inhibit the formation of fat droplets in an in vitro cell culture system that mimics the process of fat cell formation or adipogenesis. Both seed and hull extracts of all three pulses showed an inhibition of adipogenesis and the hull fraction and also contained higher levels of polyphenols compared with the seed extracts. At the molecular level, adipogenic inhibition was associated with a marked reduction in peroxisome proliferator‐activated receptor gamma (PPARG) gene expression. Furthermore, the field pea pulse extract was shown to inhibit pancreatic lipase activity at a similar level to the drug ‘orlistat’, which is commonly used to treat obesity.     

Direct evaluation of the total antioxidant capacity of raw and roasted pulses, nuts and seeds

Pulses, nuts and seeds represent an important part of human diet in many countries and epidemiological studies associated their consumption with many health benefits. These foods are often consumed after roasting that may destroy some bioactive compounds, but it can also form antioxidant compounds through the Maillard reaction. In this paper, a direct procedure for the extraction-independent measurement of the total antioxidant capacity named QUENCHER was applied to raw and roasted pulses, nuts and seeds. The results highlighted a high value of total antioxidant capacity (TAC) for some raw seed and pulses showing marked inter-varietal differences among beans examined. TAC value measured by QUENCHER was generally higher than that found using multiple extraction procedure. The effect of roasting on the TAC is the result of the thermal degradation of naturally occurring antioxidant compounds and the formation of new Maillard reaction products having antioxidant activity. In most of the foods studied, the final balance was negative with a substantial loss of antioxidant activity upon roasting. The main driver of the final TAC is the presence of reactants: in rich-starch materials, such as chickpea, cashew and borlotti beans, roasting is accompanied by a progressive increase in TAC, which is likely related with the formation of antioxidant Maillard reaction products.     

A review on technological parameters and recent advances in the fortification of processed cheese

BackgroundAlthough the consumption of processed foods is growing in overseas markets, the increased awareness of consumers to health and wellbeing in recent years has led to a decline in the growth of processed food sales in the Western market. The added pressure on the food manufacturing industry to increase the perceived healthiness of processed foods has opened up new market potential in the area of fortified processed foods, such as processed cheeses.Scope and approachThis review paper provides an overview of the current methodologies into the production of a processed cheese with added health benefits, including the use of probiotics and prebiotics, vitamin and mineral fortification and the addition of plant macromolecules.Key findings and conclusionsProcessed cheeses with increased health benefits have been of great interest to manufacturers, with reduced salt and reduced fat options commercially available. Although processed cheeses fortified with vitamins, mineral, probiotics and prebiotics are not as widespread, further work in these areas has been identified as a way to produce high value processed cheese products with added health benefits.     

Emerging technologies: chemical aspects

Consumer demands for high-quality foods with “fresh-like” characteristics that require only a minimum amount of effort and time for preparation has led to the introduction of convenience foods preserved by mild treatments. Non-thermal methods allow the processing of foods below temperatures used during thermal pasteurisation, so flavours, essential nutrients, and vitamins undergo minimal or no changes. Foods can be non-thermally processed by irradiation, high hydrostatic pressure, antimicrobials, ultrasound, filtration, and electrical methods such as pulsed electric fields, light pulses, and oscillating magnetic fields. Due to technological developments, high pressure processing and high electric field pulse processing have received increased attention during the last decade. This paper focuses on high pressure treatment of foods, a process which is also used to create food and food ingredients with new sensory and functional properties including also physiological functionality. Effects of high pressure on chemical and sensory changes in foods are discussed.     

Wholeness and primary and secondary food structure effects on in vitro digestion patterns determine nutritionally distinct carbohydrate fractions in cereal foods

Starchy foods of differing structure, including bakery products, breakfast cereals, pastas, and pulses were digested in vitro. Bakery products and processed breakfast cereals with little resilient structure yielded large amounts of rapidly available carbohydrate (RAC), less slowly digested starch (SDS) and little inaccessible digestible starch (IDS) (70:22:8%). Partially processed grains, such as rolled oats contained an increased proportion of SDS (55:38:7%). Pastas, being dense starch structures digested more gradually to completion by superficial erosion, yielding approximately equal proportions of RAC and SDS but little IDS (43:52:4%). Pulses, which retained their cellular morphology, digested more linearly yielding a lower proportion of RAC, a larger proportion of SDS and more IDS (9:69:22%). Preservation of native "primary" structure, and use of processing to create "secondary" structure, are both means by which wholeness, in the sense of intactness, can be used to influence carbohydrate digestion to make foods of lower glycaemic impact.     

Role of pulses to modulate the nutritive,bioactive and technological functionality of cereal-based extruded snacks: a review

Pulses hold excellent nutritive potential owing to high-quality protein content, dietary fibre, minerals, vitamins, oligosaccharides, polyphenols, tannins, phytosterols and several other bioactive constituents. These bio-functional compounds impart significant health benefits by reducing the risk of several chronic complications such as hypertension, cancers, cardiovascular diseases and neurological concerns mainly through anti-oxidative and radical scavenging mechanisms. These high protein ingredients when added to cereal-based extruded snacks not only enhance the nutritive and bioactive profile of the resultant snacks but also modulate the techno-functional attributes of the extrudates. Protein interactions with cereal-based starch and other constituents result in structural variation at the macromolecular level consequently varying the physical, mechanical and techno-functional properties including expansion ratio, bulk density, hydration properties, pasting characteristics and texture. The present review aimed at elaborating the nutritive and bio-functional potential of pulses enriched cereal-based expanded snacks. Further, significant emphasis has been given to the impact of pulse flour incorporation on functional, structural and mechanical properties of the cereal-based extrudates.     

Growth of Listeria monocytogenes in refrigerated ready-to-eat foods in Japan

The ability of L. monocytogenes to grow in a series of Japanese ready-to-eat (RTE) foods, including boiled baby sardine and Japanese pickle, was tested at two different refrigeration temperatures. In RTE foods in which L. monocytogenes can grow, growth was significantly higher at 10°C than that at 4°C during their shelf lives and growth patterns varied extensively among the different types of foods. However, growth did not occur at 4°C within the shelf life of certain RTE foods, such as broiled squid. The patterns of growth were varied extensively with different sample types. These results suggest that some types of traditional Japanese RTE foods stored at 10°C may be potential sources of listeriosis. To reduce the risk of food-borne listeriosis, studies to determine the contamination levels in RTE foods and the effects of storage temperature on their shelf lives are needed.