Abstract

Sumac (Rhus coriaria) is a flowering plant that is widely consumed for its promoting health benefits and used in food preparations as a spice in the Mediterranean region. It is a high shrub or small tree with imparipinnate leaves, villus and red fruits with one-seeded drupe, and small greenish-white flowers. The nutraceutical and pharmaceutical potential of sumac makes it a remarkable functional food. In this review, the phytochemical and nutritional properties of sumac as an under valorized functional food have been discussed. Flavonoids, anthocyanins, phenolic acids, and organic acids have been reported as dominant phytochemicals in sumac, which are well known for their pharmacological properties that attract many consumers to commonly choose sumac in their diet as well as food preparations. The remarkable volatile compounds present in sumac give it a unique aroma that increases its acceptance by consumers and potential use in the food industry. Sumac has been evaluated for a broad range of nutritional and pharmacological activities such as antioxidant, antinociceptive, anti-inflammatory, anti-diabetic, hepatoprotective, cardioprotective, anticancer, anti-infertility, and neuroprotective potential. This review has also briefly outlined the safety concerns concerning the use of sumac in terms of toxicology and interactions.

Introduction

Today, humanity and especially most communities in developing countries depend on medicinal plants as a valuable heritage for their primary health care and substances. Functional foods (FFs) are those foods that may promote health benefits beyond their supply of essential nutrients. Owing to its basic nutritional and nutraceutical properties, a functional food can decrease the risk of the onset of many chronic diseases, and can contribute to health[[1], [2]]. FFs can be considered as whole, fortified, enriched or enhanced foods that provide health benefits beyond the provision of essential nutrients (e.g., vitamins and minerals) when they are consumed at efficacious levels as part of a varied diet regularly[3]. Rhus coriaria, also called sumac, is a high shrub or small tree (1–3 m high) with imparipinnate leaves, villus, and red fruits with one-seeded drupe, and small greenish-white flowers organized in panicles[[4], [5]]. Given its nutritional value and its phytochemical components (flavonoids, flavones, anthocyanins, tannins, organic acids, fibre, proteins, volatile oils, nitrites, and nitrates), it has been used both as a spice and gives a sour lemon taste to various foods such as vegetables, meat dishes and rice then as a medicinal herb. It contains natural pigments such as anthocyanins and is used as coloring agents in food industry[[6], [7]]. Research efforts on sumac extracts to date indicate a promising potential of the species of this genus to provide bioproducts that have desirable biological activities: antifungal, anti-inflammatory, antimalarial, antimicrobial, antitumorigenic, antioxidant, antiviral, hypoglycaemic, anti-inflammatory, antimalarial, antimicrobial, antitumorigenic, antioxidant, and antiviral. In traditional medicine, this plant has been used in the treatment of many diseases such as cancer, stroke, diarrhoea, hypertension, dysentery, haematemesis, ophthalmia, stomach ache, diuresis, diabetes, atherosclerosis, measles, smallpox, aconuresis, teeth and gum ailments, headaches, animals bites, dermatitis and liver diseases[8]. Sumac may also have the potential for the prevention or treatment of atherosclerosis and its clinical manifestations. The target of this study was designed to evaluate sumac (R. coriaria) as an undervalorized functional food.

Conclusion

Due to the large variation in the bioactive and phytochemical content of sumac, sumac has a broad range of nutraceutical and pharmacological benefits. This makes sumac a rich functional food that can contribute to healthy living. In addition, the health promoting benefits associated with sumac can potentially increase its applications in different commercial products. More evidence and research are needed to explore the current nutritional benefits in humans through clinical trials. In fact, the more efforts could be applied to ensure that the phytochemical content of sumac is highly bioaccessible and bioavailable for more significant bioactivity. These efforts may be through encapsulating sumac and preparing different sumac formulations through complexation with other health promoting herbs or spices.

Abstract

Demand for processed food is increasing, but at the same time, some of these products have been strongly criticised for causing non-communicable diseases. Only a few studies have analysed consumers’ perceptions of food processing and, especially, ultra-processed foods. We examined consumers’ associations with processed foods, as well as how their processing and healthiness perceptions are related to food classification systems (i.e. NOVA) and the nutritional value of foods (i.e. Nutri-Score). An online survey was conducted with 498 Swiss consumers, who indicated their associations with the term ‘foods produced by the industry’. Furthermore, the respondents indicated how they perceived the healthiness and degree of processing of 27 foods that differed in how much they had been processed. The results suggest that consumers have rather negative associations with food processing. Consumers use the perceived degree of processing as a cue in their evaluation of the healthiness of foods. The use of this heuristic may result in biased decisions. Furthermore, we found a strong agreement between laypeople’s perceived level of processing and the NOVA classification system.

Introduction

Food processing plays an important role in a safe and secure food system (Carretero et al., 2020; Forde & Decker, 2022; Knorr & Augustin, 2021). The technologies behind food processing not only reduced the incidence of food-borne diseases (Floros et al., 2010) but also contributed to more sustainable food production by reducing food waste along the supply chain (Augustin et al., 2016). Furthermore, food processing has made it possible to supply a growing world population with affordable food products (Floros et al., 2010).

However, not all processed foods have high nutritional value. The way our food products are processed by the food industry has been blamed for an increase in obesity in many countries (Monteiro, 2009). Numerous studies have examined the consumption of processed foods in various European countries including Switzerland and around the world (Bertoni Maluf et al., 2022; Mertens, Colizzi, & Penalvo, ˜ 2022) . These studies have consistently found that processed foods contribute to at least 14% of total calorie intake, although the intake varies widely across Europe (Bertoni Maluf et al., 2022; De Amicis et al., 2022; Mertens, Colizzi, & Penalvo, ˜ 2022). Some studies have found that the consumption of processed foods, particularly those that are ultraprocessed, can have negative health effects, such as overweight and obesity (Monteiro et al., 2018), cardio-vascular diseases (Rauber et al., 2018), and cancer (Chang et al., 2023). However, other studies have not found a relationship between country-level burden of high body mass index and the consumption of highly processed foods (De Amicis et al., 2022; Mertens, Colizzi, & Penalvo, ˜ 2022).

Results 

Associations with ‘foods produced by the food industry’

The associations mentioned by the respondents were classified into 16 categories according to their meaning (Table 2). The associations mentioned the most commonly were ‘convenience food’ (18.7%), ‘unhealthy’ (16.5%), and ‘additives’ (10.4%). As expected, only a very small number of participants mentioned positive associations, which were mainly categorised into the ‘unspecific positive evaluations’ (3.0%) or ‘healthy’ (0.4%) categories. Furthermore, 11.8% of the participants responded to this task with ‘I don’t know’ or left the provided spot blank. The mean affect for the term evoked by ‘foods produced by the food industry’ was somewhat negative, with M = -1.06, SD = 2.32 (scale ranging from − 5 to + 5). The mean affect for the 16 categories are also shown in Table 2.

Abstract

1. Introduction

2. Data

3. Results

4. Conclusions

Acknowledgments

Disclosure statement

Funding

References

Abstract

     While a large number of studies have investigated seafood consumption in various markets, surprisingly little is known about the types of seafood sold in retail outlets or their product forms in the USA. This is particularly true for fresh seafood, which is generally regarded as the most valuable product form of seafood. In this article, a unique dataset on retail in-store seafood sales that includes information about three main product forms (fresh, frozen, and shelf-stable products) was analyzed. Fresh seafood is important, as it makes up 43% of sales revenue. Moreover, some species are almost exclusively sold fresh, with trout and lobster as prime examples. Fresh also includes the greatest diversity of species and, as such, is the most likely product form for new producers to succeed. National sales are dominated by a few species, with salmon and shrimp accounting for a large portion of the fresh (27%) and frozen categories (43%), respectively, and tuna dominating the shelf-stable category (75%). There are also a large number of species with mostly small market shares. There are few differences in regional sales patterns for the main species, with notable exceptions such as whitefish in New England and crawfish in Louisiana and Texas. The degree of urbanization and income level appears as the important drivers for seafood sales.

Introduction

     Seafood consumption in the USA has gradually increased for decades and includes a mixture of wild-caught and aquacultured species, from both domestic and imported sources (Shamshak et  al. 2019; Love et  al. 2020). As US fish stocks are generally well-managed at or near maximum sustainable yield and aquaculture production in the USA is limited, most of the increase in consumption originates from imports (Gephart et  al. 2019; Shamshak et  al. 2019). Readily available data on domestic landings, some aquaculture production, and trade enable estimates of availability (Shamshak et  al. 2019; Kroetz et  al. 2020); however, information on where seafood is consumed –in terms of both food sourcing and sub-national data, and in which product categories – is highly limited, particularly at the species level. Love et  al. (2020) recently found that about two-thirds of expenditures on seafood occurs away from home, primarily at restaurants, while seafood purchased for at home consumption makes up a much larger share by weight (56% at home vs 31% at restaurants and 13% at other outlets) (Love et  al. 2020). Moreover, these shares vary significantly by species and region. For instance, 52% of shrimp consumption occurs at home compared with 70% of salmon and 77% of tilapia consumption (Love et  al. 2020), and per capita consumption in Atlantic coastal regions is twice than that of the Midwest (Love et  al. 2020). The origin and product forms of purchased seafood are important to understand the growth in opportunities for the seafood industry – in particular in the specific market segments where domestic landings compete with typically lower priced imports – and how different parts of the seafood market respond to shocks or other sources of instability and natural variation.

Conclusions

     The US retail sector has a wide diversity of seafood species, product categories, brands, and regional sales, which makes it both complex and interesting to study. Purchases are highly focused on a handful of commodity products sold through mainstream supply chains with national distribution. Despite the diversity in seafood, which is a function of natural diversity in aquatic life (Metian et  al. 2020), the retail sector is fairly homogeneous and does not reflect the full diversity of species caught and farmed in US waters. Sales for fresh seafood vary by region, as well as by household income and urban population percentage. This suggests that better logistics and infrastructure in urban areas support fresh seafood distribution, and higher incomes allow consumers to purchase fresh products that are often at higher price points than frozen products. The opposite was true for frozen seafood, which was associated with lower household income and lower share of urban population. Shelf-stable seafood had no association with region, income, or urbanization. The Nielsen dataset does not provide insights into other food sources such as food service or self-caught seafood; however, other studies have done so (Love et  al. 2020).

Introduction

Functional foods

Importance of food texture

Impact of prebiotics

Impact of probiotics

Final considerations

References

ABSTRACT

Functional food is the trend of the future, since our current science allows the manufacturing of processed products with health benefits beyond that of the original food, which meets the demand of the modern consumers. However, many functional ingredients may affect the products characteristics, including the texture, which is very important to the consumer’s acceptance. Probiotics (Lactobacillus spp., Bifidobacterium spp., etc) and prebiotics (inulin, fructooligosaccharides, Galactooligosaccharides, etc) are widely studied functional ingredients and may change the texture of the food, improving it or not. Studies are then focusing on developing functional products with improved textural characteristics associating the healthy feature with the sensory one, thus, adding great value for these products.

INTRODUCTION

The feeding habits play a fundamental role in human’s health. That is why so many people are concerned about their health and wellness, being the life quality a reflex of a healthy and balanced eating plus the practice of physical exercises. An alternative to a better eating is to aggregate ingredients with functional value to the daily menu. Recently, the advances in food technology allows the manufacturing of several different products, both in relation to the nutritional point of view and the sensory pleasantness. The modern consumers had been very conscious about what they are consuming, then, there is an actual demand for the manufacturing of functional products, which provide additional health benefits beyond that of the original product. However, there is another trend nowadays by consumers, which associate a product with several ingredients with unhealthy characteristics, mainly artificial additives or unknown ingredients [1]; therefore, they look for “clean label” products, with reduced number of ingredients. In this way, the food industry needs to reduce the addition of stabilizers and thickeners without compromising the food texture and taste.

1- Introduction

2- Pilot study

3- Main study

4- General discussion

5- Author statement

References

Abstract

The present research included two field studies investigating, firstly, the effects of round and angular typefaces on taste expectations and, secondly, how such expectations may have downstream effects on naturalistic consumer choice. A taste experiment conducted at a science festival asked participants (N = 125) to rate the expected and actual sweetness and sourness of beer served from plastic cups labelled with either angular or round typeface. Effects of typeface were found on both taste expectations and perceived taste, but in opposite directions; participants rated the expected sourness of a beer as higher in the round (vs. angular) typeface condition, whereas they rated perceived sourness as lower in the round compared to the angular typeface condition. A follow-up field study conducted at a beer bar tested whether different typefaces on a beer board would affect actual beer choices. Data consisted of beer transactions (N = 1,952) and included the monetary amount, and the specific style, and size of beer purchased. The results showed that average transaction amount was lower in the round (vs. angular) typeface condition, and that customers purchased more sour beer options in this condition. These findings support a crossmodal compensation account, and suggest that round typefaces could increase choices of contrasting sour products. Hence, marketers may want to consider how typefaces can either enhance or diminish certain tastes.

Introduction

It has long been recognized that different typefaces have different connotations and associations. One needs to look no further than the internet’s playful disgust for typefaces such as comic sans or papyrus (Oneextrapixel, 2018) to see how people attach emotion and importance to typefaces. On a more serious note, typefaces play an important role in the development of marketing materials and product packaging design, which are often connected to significant financial costs for companies, underlining the importance of choosing the right typeface for products and brands. Certainly, typefaces can affect perception and convey meaning beyond the actual semantic message, so it is not surprising that this design element has received attention in regards to fields such as advertising and product packaging (Childers & Jass, 2002). However, even though typeface is a central part of food-related marketing, advertising, and packaging, research on the effects on taste expectation and perception has only started to gain traction (for a review, see Velasco & Spence, 2019). Indeed, several studies have shown how shapes can elicit certain associations and expectations within the food domain (Velasco et al., 2014), and other studies have revealed how, for instance, expectations play an important role in the actual perceived taste of a product (Piqueras-Fiszman & Spence, 2015).

1- Introduction

2- Experiment 1

3- Experiment 2

4- General discussion

References

Abstract

We conducted two event-related potentials (ERP) experiments to investigate consumers’ responses to different types of food bundles. In Experiment 1, the participants were instructed to indicate their wanting of a three-yogurt bundle when their neural activity was recorded. The results of self-report wanting scores revealed that the participants wanted bundles consisting of their favorite yogurt products more than those of disliked products. Such a difference in self-report scores was also indexed by the N2 in frontal brain and the P1 in the left hemisphere. By contrast, bundles consisting of three different yogurt products elicited a smaller amplitude of the N2 than bundles consisting of two favorite products and one disliked product, but these two types of bundles received comparable wanting scores. Moreover, we asked the participants in Experiment 2 to perform a visual discrimination task on these bundles, and did not found these effects on the N2 or the P1. Collectively, these results revealed neural activities underlying consumers’ responses to food rewards, and demonstrated the role of individuals’ variety-seeking tendency in wanting process.

GENERAL DISCUSSION

In summary, two major findings emerged from the present study. First, our results associated the N2 with wanting for food bundles, though this wanting effect was intertwined with liking (also see Goto et al., 2017; Telpaz et al., 2015). This result not only extended the scope from wanting for a single product to wanting for a bundle of multiple products, but also specifically linked people’s wanting for food bundles to smaller amplitude of the N2 in frontal region of the brain. Our results also associated wanting for food bundles with the posterior P1. To the best of our knowledge, the present study provides the first empirical evidence to link ERPs earlier than the N2 to wanting. This result associated the P1 to food-related cognitive processes (Becker et al., 2016), and is in line with the literature about that the P1 is sensitive to the influence of motivation (Cunningham et al., 2012; Hammerschmidt et al., 2017). Second, the results of this study revealed that the N2 may also index the differences in consumers’ responses to food rewards that cannot be easily captured by self-report ratings. That is, our results of self-report ratings did not reveal any significant difference between the 3M and 2F1D bundles, but our ERP results did reveal significant differences in the N2 elicited by these two types of food rewards. The dissociations between self-report ratings and ERPs we observed in this study are in line with the literature that people can generate motivation without conscious awareness (Winkielman, Berridge, & Wilbarger, 2005), and demonstrate that EEG signals are sensitive enough to capture the implicit processes of motivation processes (Jones, Childers, & Jiang, 2012; Pozharliev, Verbeke, van Strien, & Bagozzi, 2015).

1- Introduction

2- Materials and methods

3- Results and discussions

4- Conclusion

References

Abstract

With current global challenges such as population growth, climate change and water scarcity, it is critical to develop sustainable strategies to achieve food security. One way to tackle this is by developing new products that use alternative and more sustainable ingredients. Bambara groundnut is a low-impact African legume as it can be grown on marginal soils and is resistant to high temperatures. The aim of this study was to investigate UK consumer acceptability and emotional response to snack products containing Bambara groundnut flour as an alternative sustainable ingredient. A key objective was to understand the contribution that measuring emotional response would reveal. Additionally the impact of extrinsic information on consumer acceptability and emotional response to snack products was investigated by sharing information concerning Bambara groundnut’s sustainability and nutritional credentials. 100 UK participants were recruited to evaluate two biscotti and two cracker products. For each category a standard product made from standard ingredients sourced commercially, and one made replacing some of standard flour with Bambara flour were obtained. For each sample, participants were asked to rate their overall liking and emotional response based on sensory properties of the product (the blind condition). Participants were invited back for a second session, where they were informed about global resource challenges, and the sustainable features and nutritional value of Bambara, and which products contained this as an ingredient (informed condition). Under the blind condition, no significant differences in overall liking were observed between standard and Bambara products, indicating UK consumers accept the sensory properties of products that contain Bambara flour. Interestingly, the extrinsic information shifted consumer emotional response towards more positive emotions and less negative emotions when consuming products containing Bambara flour. It also made them felt less guilty when consuming the Bambara products, suggesting consumers engage with the idea of sustainable ingredients, and that this sustainable ingredient has potential for future new product development. It also highlighted the value of measuring emotional response for novel products to understand what may drive purchase behaviour when products are matched for liking. Food neophobia status did not impact product acceptability and emotional response between Bambara and standard products, however overall a lower emotional response was found for medium neophobic consumers in general who are more likely to evade novel products.

Introduction

Food security is defined by the United Nations as where ‘all people, at all times have physical and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life’ (World Food Summit, 1995). With current global population growth and a prediction that this will reach over 10 billion people by 2050 (FAO, 2009), the goal of improving global food security faces a number of challenges including climate change (Cox, Betts, Jones, Spall, & Totterdell, 2000) and water scarcity (Butler, 2017). Sustainable strategies that enable agricultural production increase, waste reduction, and development of alternative sustainable novel ingredients for food processing are urgently needed. With increased public interest in sustainable food products, consumer attitude and acceptance of novel sustainable food products or ingredients is an important determinant of a novel product’s implementation and commercialisation.

Key Features of Pollen Germination in Cereals

Genetic and Proteomic Screening for Key Factors in Pollen Germination

Key Pathways Identified for Pollen Germination in Cereals

Concluding Remarks

References

Germination of Pollen

In flowering plants, the distribution of pollen (see Glossary) across land by wind and/or animals drives the spread of genetic variation within a species. Agriculturally, successful fertilization of flowers in an increasingly harsh and unpredictable climate is the key determinant of grain production and yield in cereal crops [1]. Mature pollen usually contains only two cell types – sperm cells and the much larger vegetative (or tube) cell – and desiccates before release from the anther. On adhering to a compatible stigma, pollen grains respond to signals from the mother plant and become active, undergoing cytoplasmic reorganization and activation of stored RNA and protein to produce a pollen tube originating from the vegetative cell. The pollen tube elongates within the pistil until it reaches the egg cell, where the sperm cell divides to enable the double-fertilization event typical of plants (Figure 1, Key Figure).
The factors that control successful pollen germination have been the focus of plant reproduction, evolution, and breeding research to increase crop yield and to overcome hybridization barriers [1,2]. Barriers to fertilization include interspecific incompatibility as well as self-incompatibility, which maintains genetic diversity within a local population. However, overcoming some of these constraints in a breeding environment can contribute to the production of novel elite lines for specific end-uses. Since 2003, pollen transcriptomic studies, together with identified mutants, have rapidly expanded our knowledge of the regulatory mechanisms that govern the fertilization process, including signaling pathways and cytoskeleton proteins [3–11]. However, most of this research has occurred in model plant species such as arabidopsis; despite massive agronomic and economic interest, relatively little is known about these molecular processes in cereal crops (the Poaceae). This review focuses on the unique characteristics of pollen grain adhesion, hydration, germination, and pollen tube growth in monocot cereals, and provides an overview of our current understanding of the regulators governed by the male gametophyte in the best-studied species, rice (Oryza sativa) and maize (Zea mays) (Figure 1C).

1- Introduction

2- Description of the traditional process

3- Energy saving simulations and methods

4- Improvement of the desolventizer operation

5- Energy and environtal impacts of the improved process

6- Conclusions

References

Abstract

Soybean oil is widely used as cooking oil, whereas the soybean cake is a valuable ingredient for animal food. The extraction of soybean oil is an energy-intensive process, with additional significant impact on the environment via the wastewater and hexane emissions. The research investigated different ways to minimize the energy consumption. In a traditional process, both direct (live) steam and indirect steam heating (jackets, tubular exchangers) are used to deliver the required heat duty. Direct steam injection is restricted to the first evaporator and the stripper, for a total of 620 kg/h. Indirect steam is also applied in the evaporators for a total of 6.44 MW. The desolventizing process requires a steam energy input of 8.15 MW. Integration of a heat exchanger network in the evaporation and stripping part of the process reduces the amount of direct steam usage from 620 kg/h to 270 kg/h and of the indirect heat duty from 6.44 to 5.05 MW. In the cake desolventizing part of the process, the energy requirement is reduced from 8.15 to 2.12 MW. The overall gross energy saving is hence ∼50%. The improvements moreover reduce both the waste water loadings by 56.5% and the CO2 emissions by 62.5%. Hexane emissions are moreover significantly (>90%) reduced.

Introduction

Vegetable oils are commonly used for different end applications. Whereas edible vegetable oils, such as soybean, peanut, palm and sunflower oils are used in food commodities. (Alam et al., 2014), they also find applications in biodiesel or even bio-aviation fuel via transesterification and other secondary transformation processes. (Issariyakul and Dalai, 2014; Lin et al., 2009; Wang et al., 2017; Yun et al., 2013). There are also a number of oils, such as rice bran oil, palm kernel oil and sheanut butter, that are used in specific markets with added value for cosmetics and pharmaceuticals. (Cargill, n.d.) Soybeans are used worldwide for their oil and protein contents. In 2017, the world production of soybeans was 340 million ton (33.9% in America, 32.1% in Brazil, 16.2% in Argentina). The world production of soybean oil was 56 million ton. The high content of poly-unsaturated components in soya has positive effects on the human health, by e.g. reducing the blood lipids, preventing blood clots, and boosting immunity. The cultivation of soybeans moreover captures nitrogen from the air and transforms it into N-fertiliser. The main components of the soybean are proteins (36 wt%), carbohydrates (30 wt%), fat/oil (20 wt %) and water (9 wt%). The composition of the soybean oil is given in Table 1 (Carrín and Crapiste, 2008).

Gluten-free (GF) pasta has gained worldwide consumption, especially by people with various forms of gluten intolerance or suffering from celiac disease. The latter represent around 1% of the population in Europe and in the USA (Catassi et al. 2015). The demand for GF food has recently increased also in Africa, although the prevalence of celiac disease in Africa remains unknown (Catassi et al. 2015). Rice flour has been widely used as a raw material in the preparation of GF products, because of its bland taste, white color, high digestibility, and hypoallergenic properties (Fabian and Ju 2011). Compared to wheat, rice flour has low protein content and a relatively poor ability to develop a cohesive network, which impairs its technological performance (Marti and Pagani 2013). Several studies have recently emphasized the need for improving the nutritional quality of cereal-based GF products, highlighting the low content in essential micronutrients of these products when compared with their wheat-based counterparts (Pellegrini and Agostoni 2015). This has prompted a search for additional and/or alternative raw materials—including minor cereals, psudocereals, and pulses—with high nutritional profile, that have been formulated into GF staple foods such as bread (Caldero´n de la Barca et al. 2010; Marti et al. 2017) and pasta (CabreraCha´vez et al. 2012; Marengo et al. 2015). In this frame, the addition of egg albumen represents an effective strategy to improve GF pasta products (Marti et al. 2014; Phongthai et al. 2017). Addition of egg albumen provides a simple and effective way for forming within GF products a protein network capable of minimizing solid losses upon cooking and to improve some rheological traits (such as firmness) in the cooked pasta (Marti and Pagani 2013; Marti et al. 2014). Soybean is an excellent source of proteins that may provide a number of desirable functional and technological beneficial effects, along with a balanced amino acid intake (Meinlschmidt et al. 2016). Orange-fleshed sweet potato is also an interesting ingredient for GF foods. Sweet potato is widely used to prevent vitamin A deficiency in Africa, due to its high content in b-carotene (Gurmu et al. 2014; Christides et al. 2015), and provides satisfactory sensory attributes and appropriate physical properties (Mahmoud and El Anany 2014). Additionally, sweet potato shows a relatively low amount of phytates and a high content of ascorbic acid, that positively affect micronutrient bioavailability (La Frano et al. 2014). However, preparation of rice-based GF pasta incorporating materials other than cereals may present difficulties, and much attention should be paid to the use of proper ingredients and of proper procedures in the pasta-making process (CabreraCha´vez et al. 2012; Barbiroli et al. 2013; Phongthai et al. 2017).

The past decade has proven the competence of nanotechnology in almost all known fields. The evolution of nanotechnology today in the area of the food industry has been largely and has had a lot of contribution in the food processing, food package, and food preservation. The increasing global human population has come with growing population to be fed, and food production is not adjusted to at par with the growing population. This mismatch has shown the real essence of food preservation so that food products can reach to people on a global scale. The introduction of nanotechnology in the food industry has made it easy to transport foods to different parts of the world by extending the shelf-life of most food products. Even with this beneficial aspect of nanotechnology, it has not been proven an entire full-proof measure, and the field is still open to changing technology. It suffices to note that nanotechnology has to a big extent succeed in curbing the extent of food wastage due to food spoilage by the microbial infestation. Nanotechnology has focused on fresh foods, ensuring a healthier food by employing nano-delivery systems in the process. The delivery systems are the ones, which carries the food supplements. However, these are certain sets of regulations that must be followed to tame or control the health related risks of nanotechnology in food industries. This paper outlines the role of nanotechnology at different levels of the food industry including, packaging of food, processing of food and the various preservation techniques all aiming to increase the shelf life of the food products.

Introduction

The quest to improve and devise better food preservation techniques by man has existed since the prehistoric times. This antedates from the times that man used to preserve fresh kill in caves. The caves had a dampened environment which kept the kill fresh for some time. The invention of refrigeration techniques in the 21st century then ensued. The use of cellars as well as cold streams were other traditional methods used for food preservation (Alfadul and Elneshwy, 2010). Fermentation and drying existed in the early BCs and what is used today are just improved and modified versions of these concepts (Chellaram et al., 2014). There are a number of popular methods of food preservation that have been used by man in day to day basis including sun drying, roasting, fermenting, salting, smoking, oven baking, carbonation of foods and chemical use or artificial preservatives. The basic working principle behind all these preservation methods rotated around two ideas; slowing down the multiplication of microbial agents or killing them. However, none of the methods were to put use with the complete understanding of the scientific mechanisms behind each of them. There has been evidence of the utilization of these methods of food preservation in the past where the Romans were famous for the introduction and use of pickling for prevention of microbial infestation of the food, while the Egyptians were known for using sun-drying to prevent their foods from spoiling (Abbas et al., 2009). Food jellying by use of honey or sugar was associated with the Greeks as a preservation technique. The first technology innovative breakthrough in preservation techniques came in 1784 by William Cullen who made a crude method of artificial refrigeration. Canning technique and salting of food began in the early 1800s to keep food fresh for a longer period (Abbas et al., 2009). Many scholars in the early 1800s made significant discoveries in preservation techniques; Nicolas Appert, known for the invention of vacuum bottling for the supply of the French troops with food, opened the way for tinning and then canning by Peter Durand in 1810. In 1862, Louis Pasteur introduced pasteurization that enabled wine, beer, and milk to have an extended shelf life.

Basics Considerations on Enzymes

Enzymes have been used for millennia in food processing, such as bread baking, brewing, cheese and wine making, although only in the later decades of the 20th century, processes were developed that allowed the production in well-characterized formulations, even at large scale (Kirk et al., 2002; Mishra et al., 2017). Enzymes are globular proteins that act as catalysts, thus they speed up the rate of a reaction by lowering the energy of activation. Some enzymes require cofactors, small organic molecules or metal ions, for catalytic activity. Unlike chemical catalysts, enzymes are natural in origin, operate under mild temperature and pressure, display high specificity and are biodegradable (van Oort, 2010; Subin and Bhat, 2015). Biologically active enzymes can be obtained from animals, microorganisms and plants, but microbial sources are favored. Microbial enzymes can be produced in high yield, in relatively low-cost and short time processes, and are typically more stable than enzymes from the remaining sources. Particularly preferred are microbial produced enzymes that are secreted to the fermentation medium, as this eases separation and purification. Genetically modified microorganisms expressing exogenous enzymes (from plant or animal sources and from pathogenic or difficult to grow microbial strains) are also used in commercial enzyme production (Chandrasekaran et al., 2015; Subin and Bhat, 2015). Enzyme activity and stability are influenced by operational conditions, e.g., pH, temperature, substrate concentration, presence of metal ions and enzyme concentration. Enzymes have optimal pH and temperature conditions for activity and stability that may not fully match in an industrial process. An increase in substrate concentration increases activity up to a given point, henceforth the rate of reaction stabilizes or may even decrease, in case of substrate inhibition. Also depending on the enzyme, given metal ions may be required for activity (e.g., Ca2þ for most a-amylases), or may inhibit enzyme activity (Subin and Bhat, 2015). Thus, careful selection of operating conditions is critical for high enzyme performance. This is relatively easy to implement in laboratory condition with model systems, but may prove difficult to reproduce with real systems, due to the complexity of the matrix to be processed, e.g., hydrolysis of lactose in buffer system or industrial scale hydrolysis of lactose in milk. Enzymes can be used in free form or immobilized, e.g., attached to/entrapped in an inert support, to allow the repeated/continuous use of the enzyme, and to also increase its stability. Still, the implementation of an immobilized enzyme based system at industrial scale requires a careful evaluation as in addition to technical issues, e.g., loss of activity during immobilization, mass transfer limitations, the economics of immobilized enzymes, e.g., cost of immobilization, cost of immobilization carrier and chemicals for immobilization, must be considered (DiCosimo et al., 2013; Sheldon and van Pelt, 2013).