Effect of dry‐heat treatments on the nutritional value of maize germ

Maize germ is a by‐product of the maize milling process that is characterised by a high nutritional value. Currently, heat treatments are employed to prevent full‐fat maize germ from spoilage. The aim of this research was to study the effect of five dry‐heat treatments on the nutritional value of full‐fat maize germ. The results confirmed that after each dry‐heat treatment, the lipase activity decreases but the use of high temperatures could be detrimental for phytosterol and thiamine concentrations. The main negative effects have been observed after treatments at 140 °C for 30 min and 160 °C for 10 min. No significant difference has been observed for protein, ash or fatty acid contents. The treatment at 140 °C for 20 min resulted an optimal combination between temperature and heating time to inactivate lipase without altering deeply the nutritional value and the colour of maize germ.     

Maize: A Paramount Staple Crop in the Context of Global Nutrition

Abstract: The maize plant (Zea mays), characterized by an erect green stalk, is one of the 3 great grain crops of the world. Its kernels, like other seeds, are storage organs that contain essential components for plant growth and reproduction. Many of these kernel constituents, including starch, protein, and some micronutrients, are also required for human health. For this reason, and others, maize has become highly integrated into global agriculture, human diet, and cultural traditions. The nutritional quality and integrity of maize kernels are influenced by many factors including genetic background, environment, and kernel processing. Cooking procedures, including nixtamalization and fermentation, can increase accessibility of micronutrients such as niacin. However, man cannot live on maize alone. For one‐third of the world's population, namely in sub‐Saharan Africa, Southeast Asia, and Latin America, humans subsist on maize as a staple food but malnutrition pervades. Strategies to further improve kernel macronutrient and micronutrient quality and quantities are under intense investigation. The 2 most common routes to enhance grain nutritional value are exogenous and endogenous fortification. Although exogenous fortification, such as addition of multivitamin premixes to maize flour, has been successful, endogenous fortification, also known as “biofortification,” may provide a more sustainable and practical solution for chronically undernourished communities. Recent accomplishments, such as low‐phytate, high‐lysine, and multivitamin maize varieties, have been created using novel genetic and agronomic approaches. Investigational studies related to biofortified maize are currently underway to determine nutrient absorption and efficacy related to human health improvement.     

Effects of Germination on the Nutritional Properties,Phenolic Profiles,and Antioxidant Activities of Buckwheat

Germination is considered to be an effective process for improving the nutritional quality and functionality of cereals. In this study, changes of nutritional ingredients, antinutritional components, chemical composition, and antioxidant activities of buckwheat seeds over 72 h of germination were investigated, and the reasons for these changes are discussed. With the prolonged germination time, the contents of crude protein, reducing sugar, total phenolics, total flavonoids, and condensed tannins increased significantly, while the levels of crude fat, phytic acid, and the activity of trypsin inhibitor decreased. Phenolic compounds, such as rutin, vitexin, isovitexin, orientin, isoorientin, chlorogenic acid, trans‐3‐hydroxycinnamic acid, and p‐hydroxybenzoic acid increased significantly during the germination process, which may be due to the activation of phenylalanine ammonialyase. The improvement of flavonoids led to significant enhancement of the antioxidant activities of germinated buckwheat. Germinated buckwheat had better nutritional value and antioxidant activities than ungerminated buckwheat, and it represented an excellent natural source of flavonoids and phenolic compounds, especially rutin and C‐glycosylflavones. Therefore, germinated buckwheat could be used as a promising functional food for health promotion.     

Nutritional assessment of transgenic lysine‐rich maize compared with conventional quality protein maize

BACKGROUND: The gene sb401 encoding a lysine‐rich protein has been successfully integrated into the genome of maize (Zea mays), its expression showing as increased levels of lysine and total protein in maize seeds. As part of a nutritional assessment of transgenic maize, nutritional composition, especially unintended changes in key nutrients such as proximates, amino acids, minerals and vitamins as well as in antinutrient (phytate phosphorus), and protein nutritional quality were compared between transgenic maize (inbred line 642 and hybrid line Y642) and conventional quality protein maize (QPM) Nongda 108. RESULTS: The contents of total protein, lysine, some other amino acids, several minerals and vitamin B₂ in transgenic inbred line 642 and hybrid line Y642 were significantly higher than those in conventional QPM. Water‐soluble protein and G2‐glutelin were significantly promoted in transgenic maize Y642. CONCLUSION: Insertion of the lysine‐rich sb401 gene increased the total protein and lysine content of transgenic maize varieties, leading to an improved amino acid score and therefore an improvement in the nutritive value of maize. © 2013 Society of Chemical Industry     

Effect of thermal processing on the degradation, isomerization, and bioaccessibility of lycopene in tomato pulp

Thermal processing affects the nutritional value of food products. The nutritional value is not only determined by the content but also by the bioaccessibility of nutrients. The present study was performed to gain detailed insight into the influence of thermal processing on the degradation, isomerization, and bioaccessibility of lycopene isomers in tomato pulp, without adding any other ingredient. The bioaccessibility, which is defined as the fraction of the nutrient that can be released from the food matrix, was measured using an in vitro method. The results demonstrated the rather high thermal stability of lycopene. Although a treatment at 140 °C induced isomerization, the contribution of cis-lycopene to the total lycopene content remained small. Results also confirmed that thermal processing as such can improve the in vitro bioaccessibility of lycopene in tomato pulp, but the improvement was only significant upon treatments at temperatures of 130 and 140 °C. At such intense process conditions, one should be aware of the negative effect on other quality and nutrient parameters. Possibilities of thermal processing as such to improve the nutritional value of tomato pulp (without the addition of other ingredients) thus looks rather limited.     

The FAST method,a rapid approach of the nutritional quality of heat‐treated foods

The FAST method is based on the determination of maximal fluorescence emission when exciting at 330–350 nm, which corresponds to molecular structures formed between reducing sugars or oxidizing lipids and lysine residues of proteins. This fluorescence is dependent on heat treatment and related to protein nutritional loss. Applied to a soluble extract of the food and corrected for the protein concentration of the solution obtained, using Trp fluorescence, the method allows to calculate the FAST index (FI( an indicator of the nutritional damage during heat process. The method, firstly validated on milk samples, is demonstrated here to well correlate with lysine damage on various food products, such as heat‐treated milk and breakfast cereals, essentially modified by the Maillard reaction, and roasted soybean or cooked salmon, where interactions between oxidizing lipids and proteins better take place. Independently on the food product or the type of heat process, the FAST index appears always well correlated (r²: 0.84–0.98) to the lysine loss, the latter being estimated by determination of acid‐released lysine, fluorescamine‐reactive lysine or infrared. Shortly, roasted corn flakes appeared to be more damaged than extrudated flour (FI 100 and lysine blockage 40% instead of 55 and 30%( condensed milk more than UHT milk (FI 150 and 85% of acid‐released lysine instead of 80 and 94%( and steam‐cooked salmon much less than pan‐fried (FI 28 instead of 372). Roasted soy can reach FI of more than 300 corresponding to chemical lysine loss of 40% and poultry‐digestive lysine loss of 100%. As a conclusion, the FAST method, once precisely calibrated with pertinent nutritional indicators, should be of great interest for controlling or adapting a process in order to ensure a better nutritional quality for the food product.     

Cholesterol Oxidation in Fish and Fish Products

Fish and fish products are important from a nutritional point of view due to the presence of high biological value proteins and the high content of polyunsaturated fatty acids, especially those of the n‐3 series, and above all eicosapentaenoic acid and docosahexaenoic acid. However, these important food products also contain significant amounts of cholesterol. Although cholesterol participates in essential functions in the human body, it is unstable, especially in the presence of light, oxygen, radiation, and high temperatures that can cause the formation of cholesterol oxidation products or cholesterol oxides, which are prejudicial to human health. Fish processing involves high and low temperatures, as well as other methods for microbiological control, which increases shelf life and consequently added value; however, such processes favor the formation of cholesterol oxidation products. This review brings together data on the formation of cholesterol oxides during the preparation and processing of fish into food products which are recognized and recommended for their nutritional properties.     

Honey—its characteristics,sensory aspects,and applications

Abstract

Honey is a natural, sweet, syrupy fluid collected by bees from nectar of flowers. The pleasant aroma and taste of this viscous liquid ranging in color from pale yellow to dark amber varies according to geographical and seasonal conditions. Its use as a sweetener is well known in different parts of the world. In early history, honey occupied a very important place on religious occasions. The high content of sugars, small amounts of amino acids, lipids, along with some vitamins and minerals imparts its high nutritional value. Honey has good medicinal and antimicrobial properties and is used in different cuisines. Proper processing is essential for a product of good sensory qualities. ISI/Agmark specifications for honey, its adulteration and detection of adulteration are well recorded. The application potential in bakery, confectionery, snack foods, fruit and vegetable products and beverages is ever increasing. A bird's‐eye view of these aspects along with possible lines of future research are discussed.     

Application of High Pressure with Homogenization,Temperature, Carbon Dioxide,and Cold Plasma for the Inactivation of Bacterial Spores: A Review

Formation of highly resistant spores is a concern for the safety of low‐acid foods as they are a perfect vehicle for food spoilage and/or human infection. For spore inactivation, the strategy usually applied in the food industry is the intensification of traditional preservation methods to sterilization levels, which is often accompanied by decreases of nutritional and sensory properties. In order to overcome these unwanted side effects in food products, novel and emerging sterilization technologies are being developed, such as pressure‐assisted thermal sterilization, high‐pressure carbon dioxide, high‐pressure homogenization, and cold plasma. In this review, the application of these emergent technologies is discussed, in order to understand the effects on bacterial spores and their inactivation and thus ensure food safety of low‐acid foods. In general, the application of these novel technologies for inactivating spores is showing promising results. However, it is important to note that each technique has specific features that can be more suitable for a particular type of product. Thus, the most appropriate sterilization method for each product (and target microorganisms) should be assessed and carefully selected.     

High‐Amylose Starches to Bridge the “Fiber Gap”: Development,Structure, and Nutritional Functionality

Although high‐amylose starches are not a recent innovation, their popularity in recent years has been increasing due to their unique functional properties and enhanced nutritional values in food applications. While high‐amylose maize, barley, and potato are commercially available, high‐amylose variants of other main crops such as wheat and rice have once been developed more recently and will be available commercially in the near future. This review summarizes the development, structure, and nutritional functionality of high‐amylose starches developed and reported so far. The range of biotechnological strategies utilized are reviewed, as are the consequent effects on structural properties at different length scales, as well as sensory aspects of foods containing high‐amylose starch (HAS). This review identifies the molecular and microstructural features contributing to digestive enzyme resistance not only in native HAS but also in forms of relevance to food processing. During heat treatment, HAS tends to retain or form dense molecular structures that resist amylase degradation through the retention of the granular structure as well as helices (type‐2 resistant starch [RS]), reassociation of glucan chains (type‐3 RS), and formation of lipid–amylose complexes (type‐5 RS). The review also identifies opportunities for food manufacturers and consumers to incorporate HAS in food products and diets for better nutritional outcomes.     

Development of a nutritional profile predicting tool for fresh and processed tomato‐based products

This study was aimed at developing a tool to represent the evolution of nutritional profile of food during processing with input data mined from previous published papers or database on composition and reactivity of nutrients, and from minimal experimentations. Tomato‐based products, that is tomato sauce, concentrate and paste, were chosen to evaluate the developed model. The SAIN‐LIM system was used to assess the nutritional profile of the tomato products throughout the process steps, including seven constituents: five basic nutrients (i.e. proteins, fibres, vitamin C, calcium and iron) and two microconstituents found in tomato: β‐carotene and lycopene. The SAIN‐LIM nutritional profiles obtained with this model were compared to that calculated from experimental data. Calculated and experimental nutritional scores showed that process steps involved in tomato‐based products did not affect substantially their nutritional quality. Observed differences were mainly attributed to the kinetic parameter selection and raw product variability. The conclusion offers suggestions to extend the model to other product/process combinations.     

Nutritional,functional and biological properties of insect proteins: Processes for obtaining,consumption and future challenges

BackgroundConsuming insects as an alternative protein source is considered a future trend and a viable strategy that could potentially contribute to global food security. Insects are a non-conventional source of protein, either for human consumption directly or indirectly as a component in recomposed foods or added to feedstock mixtures. Moreover, these proteins have demonstrated a broad range of applications as peptides with antihypertensive, antimicrobial and antioxidant properties. However, aspects such as food safety and processing of these proteins need further studies for their elucidation and optimization.Scope and approachIn this review, aspects of nutritional value and risks of insect consumption are reported. Additionally, conventional processing techniques and recent advances in insect protein extraction and production are presented. The application of bioactive peptides obtained from insect protein hydrolysates is reported, focusing on their potential antihypertensive, antimicrobial and antioxidant properties.Key findings and conclusionsInsect proteins have great advantages in terms of nutritional value, total protein level and amino acid profile. However, some safety concerns must be taken into consideration in large-scale production. The conventional processing of insects proteins is very particular, depending on several aspects such as species, larval stage, and cultivation, among others. Nonetheless, recent advances in insect protein production via enzymatic hydrolysis and heterologous expression have shown a promising technology for the study and exploitation of their bioactive properties, such as the antimicrobial, antioxidant and antihypertensive (inhibition of ACE) activity of insect peptides.     

Applications of chia (Salvia hispanica L.) in food products

BackgroundThe outstanding nutritional and technological properties lead to innovative applications of chia (Salvia hispanica L.) in food products.Scope and approachThe aim of this contribution is to give an overview of the various food application approaches for chia. The nutritional and technological properties of chia as well as its technological and innovative utilization are presented. Examples for the various applications in food products are given in five main topics: baked goods, dairy products, meat and fish products, gluten-free products and other products such as functional food, hydrocolloid and thickener.Key findings and conclusionsBesides the nutritional benefits of chia incorporation in food products the technological effects are emphasized very often. Summarized in five main topics, most authors conclude that chia is a valuable food ingredient for functional food development. The application of chia in baked goods for example is beneficial not only to improve the nutritional value but acting as hydrocolloid or substitute egg, fat or gluten. The increase of oil stability and applications as food thickener in novel food applications are of high importance too. As different chia fractions give various options for applications the utilization of chia for further food products will increase significantly in the future.     

Nutritional status affects the absorption and whole-body and organ retention of cadmium in rats fed rice-based diets

Staple grains such as rice, wheat and maize consumed by different societal groups differ greatly in their concentrations and bioavailability of the cadmium (Cd) antagonists, zinc (Zn), iron (Fe), and calcium (Ca). We hypothesized thatthe low nutritional status of rice consumers, which results from an inadequate supply of these minerals from rice, could contribute significantly to a higher apparent susceptibility to soil Cd contamination from rice than the higher nutritional status of those who consume other grains with higher mineral content. To test this hypothesis, a 2 x 2 x 2 factorial study was conducted. Rats were fed diets with adequate or marginal amounts of dietary Zn, Fe, or Ca. The basal diets contained 40% unenriched, milled rice fortified with 0.62 mg of Cd/kg as CdCl2 (0.25 mg of Cd/kg diet). Rat consumed the diets for 5 weeks and then were fed 1 g of a similar diet containing 10(9)Cd-labeled rice. After 2 weeks, whole-body (WB) retention of 109Cd was determine. Rats then were killed, and the organs were removed for total Cd determinations. Rats fed marginal concentrations of dietary Zn had slightly but significantly more WB retention of 109Cd than controls; however, rats fed marginal Fe or Ca had as much as 3-fold higher retention of the label. Rats fed marginal amounts of Zn, Fe, and Ca combined retained as much as 8 times more 109Cd than rats fed adequate minerals. The effects on Cd concentrations in liver and kidney were similar to the effects on 109Cd retention. These results support the hypothesis that populations exposed to dietary sources of Cd and subsisting on marginal mineral intakes could be at greater risk than well-nourished populations exposed to similar amounts of dietary Cd. Thus, different food crops can cause unequal Cd risk at equal Cd concentration if diets containing the food are not balanced to provide adequate interacting mineral concentrations.     

Physicochemical characteristics,bioactive compounds and industrial applications of mango kernel and its products: A review

Mango (Mangifera indica L.) is a fruit plant of family Anacardiaceae, widely grown all over the world, and is a very popular fruit in the world market. Mango fruit is the second most traded tropical fruit and fifth in terms of production globally. Large quantities of mango processing coproducts are generated (peels and seeds), which usually are discarded as waste, yet are a potential source of fat, protein, carbohydrate, and certain bioactive compounds. Mango kernel is a remarkably rich source of macronutrients and micronutrients including calcium, potassium, magnesium, phosphorus, and vitamins A, E, K, and C. Phytochemicals with a notable therapeutic potential such as tocopherols, phytosterols, carotenoids, polyphenols (gallotannins, flavonols, benzophenone derivatives, mangiferin, homomangiferin, isomangiferin, anthocyanins, kaempferol, and quercetin), and phenolic acids (4‐caffeoylquinic acids, caffeic, coumaric, ellagic, gallic, and ferulic acid) are reported. The phytochemicals have high antioxidant, antimicrobial, anticancer, and, antiproliferation activities and could be used for food, cosmetic, and pharmaceutical applications. The nutritional composition of mango kernel constitutes 32.34% to 76.81% carbohydrate, 6% to 15.2% fat, 6.36% to 10.02% protein, 0.26% to 4.69% crude fiber, and 1.46% to 3.71% ash on a dry weight basis. The nutritional profile of the kernel suggests its usability as a food ingredient in the development of value‐added products such as mango kernel oil, mango kernel butter, mango kernel flour, and biofilms among other diverse products. This comprehensive systematic review explores mango kernel as a potential and novel food ingredient to meet the needs of a health‐conscious population. The review also provides a remedy to waste management and environmental pollution.     

Functional Applications of Lignocellulolytic Enzymes in the Fruit and Vegetable Processing Industries

Cellulose, hemicellulose, pectin (carbohydrate), and lignin (noncarbohydrate) polymers are the main substrates of lignocellulose‐degrading enzymes. They are present in large amounts in the primary cell wall and dietary fibers of major fruits and vegetables. During processing of fruits and vegetables to the corresponding final food products, lignocellulosic substrates are hydrolyzed by different lignocellulolytic enzymes. Currently, lignocellulolytic enzymes such as cellulases, xylanases, pectinases, and laccases are extensively used during the processing of fruits and vegetables, in applications like texturizing and flavoring of products in the food industries. The present article provides an updated overview of functional applications of lignocellulolytic enzymes in the juice processing, oil extraction, and alcoholic beverage processing industries. Extensive use of lignocellulolytic enzymes in different food processing industries not only accelerates the production rates but also improves product quality. It is also possible to ensure the efficient use of fruits and vegetables globally by employing lignocellulolytic enzymes in the corresponding processing industries to convert them into food commodities, which will not only raise their economic value in the global market but also increase food availability, which will help mitigate nutritional problems worldwide.     

Minimally Processed Functional Foods: Technological and Operational Pathways

This paper offers a concise review of technical and operational concepts underpinning commercialization of minimally processed functional foods (FFs), foods with fresh‐like qualities commanding premium prices. The growing number of permitted nutritional content/health claims, many of which relate to well‐being, coupled with emerging extraction and food processing technologies offers new exciting opportunities for small and medium size enterprises (SMEs) specializing in fresh produce to play an active role in the health market. Supporting SMEs, governments could benefit from savings in healthcare costs and value creation in the economy. Consumers could benefit from novel FF formats such as refrigerated RTE (ready‐to‐eat) meals, a variety of fresh‐like meat‐, fish‐, and egg‐based products, fresh‐cut fruits and vegetables, cereal‐based fermented foods and beverages. To preserve these valuable commodities, mild biological (enzymatic treatment, fermentation and, bio‐preservation) and engineering solutions are needed. The latter include nonthermal techniques such as high‐pressure treatment, cook‐chill, sous‐vide, mirco‐encapsulation, vacuum impregnation and others. “De‐constructive” culinary techniques such as 3D food printing and molecular gastronomy as well as developments in nutrigenomics and digital technologies facilitate novel product formats, personalization and access to niche markets. In the operational sense, moving from nourishment to health improvement demands a shift from defensive market‐oriented to offensive market‐developing strategies including collaborative networks with research organizations.     

Assessment for fungal,mycotoxin and insect spoilage in maize stored for human consumption in Zambia

BACKGROUND: Maize constitutes the main staple food and most important crop grown in Zambia. However, maize incurs considerable losses both in field and storage due to pathogens and insects. Some of the pathogens and resultant mycotoxins reduce the nutritional quality of the product. Mycotoxins are toxigenic fungal compounds that can cause cancer and suppress growth. In spite of this health hazard, there has been very little research to document their occurrence. Maize grains stored for human consumption were sampled from different agro‐ecosystems (forest, valley and plateau areas) of three agroecological zones (high, mid and low altitude). RESULTS: Several fungal genera were recovered among which Aspergillus flavus, A. niger, Fusarium verticillioides, F. solani, Rhizopus stolonifer and Penicillium spp. were prevalent. The weevil Sitophilus zeamais and the larger grain borer Prostephanus truncatus were the most damaging. Enzyme‐linked immunosorbent assay (ELISA) tests yielded fumonisins and aflatoxins ranging between 0.02 and 21.44 ppm, and 0.7 and 108.39 ppb in 96.4% and 21.4% of samples, respectively. Fumonisin was more pronounced in villages in forest areas whereas aflatoxin was highest in valley and forest areas in Zone II. CONCLUSION: Strategic interventions to curtail fungal, mycotoxin and insect contamination should be directed towards improved agronomic and post‐harvest practices of maize from fields to consumers. Copyright © 2009 Society of Chemical Industry     

Dielectric determination of bio‐ and free‐calcium in commercial alkaline‐cooked ground corn

Using dielectric measurements, it was possible to determine the concentration of bio‐ and free‐calcium in a corn dough prepared mixing commercial powder of alkaline‐cooked ground‐corn kernel (maize), Zea mays, with different concentrations of Ca(OH)₂ and the same amount of water. This allows determining the conditions to obtain dough with high bio‐calcium content and consequently high nutritional value. The samples were placed in the interior of a small parallel‐plate capacitor. The capacitance and the cell current profiles were obtained with the corresponding relaxation times as a function of the Ca concentration. With this information, it was possible to determine the threshold concentration at which the Ca ions are not longer linked chemically to the cornstarch molecules and move freely in the interior of the dough. A model based on the ionic conductivity was developed to explain the dependence of the relaxation times with the Ca concentration.     

Effect of the high-pressure assisted-infusion processing on nutritional and antioxidant properties of mango cubes

The aim of this work was to evaluate the effect of the high-pressure assisted-infusion processing on the nutritional and functional properties of mango cubes immersed in a solution of sorbitol and calcium lactate. Three factors were studied: sorbitol concentration (20°Brix-40°Brix-60°Brix), calcium lactate concentration (0% w/w − 1% w/w − 2% w/w) and the pressure level (0.1 MPa–300 MPa-600 MPa). Sugar (sorbitol, glucose and sucrose), calcium and total phenols content and antioxidant capacity were determined. Results showed that the increase of sorbitol concentration from 20°Brix to 40°Brix caused higher sorbitol uptake and lixiviation of the natural compo in mango cubes. However, the increase of sorbitol concentration from 40°Brix to 60°Brix, had no significant effect on the diffusion of solutes. The high-pressure processing (HPP) favored the diffusion of solutes from solution to fruit, while the addition of the calcium counteracted this effect in most cases. Based on these results, the combined effect of 300 MPa and 60°Brix-2% calcium lactate was the most effective at preserving natural compounds of mango and conferred distinctive properties giving an added value to the final product due to its important nutritional implications. Therefore, high-pressure assisted-infusion processing could be considered as an effective method to preserve mango cubes with an acceptable nutritional value.Industrial relevanceThe present work showed that high-pressure assisted-infusion processing could be considered an alternative to develop mango-based products. Results showed that this process would allow preserving most of the natural compounds of the mango pieces, in addition to achieving distinctive characteristics, as a source of calcium. Therefore, the application of high-pressure assisted-infusion processing could open new opportunities for food industries to develop fresh and value-added products with characteristics similar to fresh fruit.