Sugary solutions

Abstract

Food Science and TechnologyVolume 37, Issue 1 p. 26-31 FeaturesFree Access Sugary solutions First published: 08 March 2023 https://doi.org/10.1002/fsat.3701_7.xAboutSectionsPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Julian Cooper and Karen Pardoe are both experts in the field of sugar chemistry having over 70 years’ experience between them. Working with sugar enabled them to build up a wealth of experience in sugar replacers and a deep understanding of the exacting requirements to replace sugar in products. Here they outline the challenges related to sugar reduction in foods. Reformulation for sugar reduction – consideration of a multifunctional ingredient Reformulation to reduce fat, sugar, and salt in foods has been a focus for many years due to concerns about how high intakes of any of these may affect human health. Globally, there is increasing pressure on manufacturers to improve the nutritional profile of processed foods through reformulation. There are various options available for sugar replacement, but no single ingredient can match the multi-functionality that sugar can provide. Additionally, there is ambiguity in how sugar is categorised in food labelling: terms such as total, added, free, extrinsic, or intrinsic sugars are not well-defined or globally accepted, nor is there an agreed protocol for measurement of these across all food products. In addition to any legislative requirement for sugar reduction, there is a growing interest in the public for ‘healthy’ alternatives to sugar that are also sustainable. Interpretation of what is ‘healthy’ is inconsistent but often appears to be based on the perceptions that sugar is ’bad’ and that what is meant by sugar is white, granulated sucrose. Sugar definition The common assumption is that the term ‘sugar’ refers only to sucrose (i.e., white granulated sugar). However, that is not the case regarding sugars present in foodstuffs and nutritional labelling. Different sugars are typically present in food products, the most common being glucose, fructose, galactose, sucrose, maltose, and lactose. The ‘-ose’ suffix indicates that the material is a type of sugar. The IFST's Food Science Information Statement on sugars[1] provides a good guide concerning the occurrence, chemistry, and different ways sugars can be defined. To better understand the use of sugars in foodstuffs, it is useful to understand the most common sources. Sugars are typically derived from plant sources, with the notable exception of lactose which is derived from milk. The plant-derived sugars can be divided into sucrose-based sugars (Figure 1) and starch-based sugars (Figure 2). Figure 1Open in figure viewerPowerPoint Sucrose-based sugars Figure 2Open in figure viewerPowerPoint Starch-based sugars The starting point for sucrose-based sugars is either sugar beet or sugarcane. These are plants that can both produce sugars by photosynthesis. The sucrose extracted from such plants can come in various formats, such as granulated sugar, icing sugar, brown sugar, liquid sugar, etc. Sucrose can then be converted into other sugars via hydrolysis, enzyme conversion, complex chemical reactions, and selective separation after chemical treatment. Hydrolysis breaks the bond between the two monosaccharides (glucose and fructose) that are bonded to produce sucrose. The hydrolysis of sucrose requires it to be in solution, as liquid sugar or sugar syrup, and the syrup produced from the hydrolysis is commonly known as invert syrup. Invert syrup is effectively a 50:50 mixture of glucose and fructose but may also contain sucrose, either through control of the hydrolysis reaction or the addition of sucrose after complete hydrolysis. Glucose and fructose in invert syrup can be separated using appropriate chromatographic resins to produce a high-concentration fructose syrup. Somewhat surprisingly, several sugar replacers are also produced from sugars obtained from sugar beet or sugar cane. These include sucralose, iso-maltulose, isomalt, and allulose. The sugars can also be used as fermentation feedstocks for other sugar replacers such as Rebaudiosides[2] which are the sweetening compounds in steviol glycosides. More complex reactions are required to manufacture these products, and their manufacturing is separate from the production of crystalline sucrose. The starting point for starch-based sugars is typically maize, wheat or potatoes, as these are the most economically viable sources for current practises. Again, the plants produce starch and sugars by photosynthesis, but sucrose concentration is insufficient for simple extraction and crystallisation (as is done for sugar beet and sugar cane). Instead, starch is extracted from the plants and hydrolysed to produce sugars. The hydrolysis reaction results in a mixture of starch and sugars, which can be described in terms of least and most hydrolysed products. Maltodextrins are the least hydrolysed and are a mixture of polysaccharides, typically consisting of three to twenty bonded glucose molecules, and are indicative of starch being only partially hydrolysed. Glucose syrups result from more extensive hydrolysis of the starch to a mixture of sugars, typically from 32% to 95% sugars, often referred to as dextrose equivalent (DE). DE indicates the level of hydrolysis the syrup has experienced, with syrups that contain more sugars being sweeter and less viscous than those with lower sugar content. Further processing of the highest sugar-content-based glucose syrup can be done to produce syrups such as iso-glucose (fructose content >10% but <50%), fructose, and high fructose corn syrup (HFCS, 42 to 55% fructose). All these glucose and fructose products are considered to be typical sugars produced from starch. More complex reactions and processes are required to produce sugar replacers such as sorbitol, mannitol, and allulose. Again, as was found for sugar replacement products from sucrose, the manufacture of sugar replacers from starch is typically separate from the production of glucose syrups Sugars regulations Even with a better understanding of what ‘sugar’ and ‘sugars’ mean, this does not directly translate into how sugar is stated concerning regulations and food labelling. Sugars are regulated under EU[3, 4] and UK[5] regulations which define their characteristics and provide reserved descriptions that must be used in labelling. Similar specifications are also listed in Codex Alimentarius[6]. The Codex Alimentarius sets international food standards, guidelines and codes of practice that are supposed to contribute to the safety, quality and fairness of the global food trade. A comparison of the regulations for white sugar is shown as an example, in Table 1. The test methods required to meet the regulations are also defined within the regulation documents and are specific to the sugar industry. Table 1. Comparison of EU/UK and Codex regulations for white sugar NS – not specified. *The figure quoted is calculated according to the methodology stated in the regulation, to provide a comparative Parameter EU/UK(England) Codex Polarisation/ Polarimetric sucrose content ≥ 97 °Z ≥ 97 °Z Sulphur dioxide NS ≤ 15 mg/kg Conductivity ash ≤ 0.027% by weight* ≤ 0.04 g/100g Invert sugar content ≤ 0.04% by weight ≤ 0.04 g/100g Loss on drying ≤ 0.06% by weight ≤ 0.1 g/100g Colour in solution ≤ 45 IU* ≤ 60 IU The globally recognised body for the analysis of sugar is the ICUMSA® Ltd. Definition for the units of measurement and full method details for the tests required by the regulations are available within the ICUMSA® Ltd Methods Book. These sugar regulations are for specific classes and compounds and are not directly related to food labelling requirements. Nutritional labels list sugars as a subheading under carbohydrate content, wherein carbohydrates are the sugars (as described in terms of typical sugars in the previous section) and starches present in the product. There are several terms used for dietary sugars in food labelling; they include total, added and free sugars. These terms aren't universally defined although local or regional definitions may be available. Prior to 2015 the UK defined free sugars as Non-Milk Extrinsic Sugars (NMES)[3]. The Scientific Advisory Committee on Nutrition (SACN) (review in 2015[7]) recommended a change to Free Sugars, very similar to the WHO definition. The term ‘added sugars’ is recommended by the Dietary Guidelines Advisory Committee (DGAC) in the United States[8]. Table 2 lists generally accepted definitions for total, free and added sugars. Table 2. Generally accepted definitions of total, added and free sugars Term Definition Total sugars All mono- and disaccharides present in food, derived from any source. Free sugars All mono- and disaccharides except those that are naturally occurring and present in the whole fruit and vegetables or dairy products but including all sugars added by the manufacturer, cook or the consumer as well as sugars that are naturally present in honey, syrups, juiced or puréed fruit or vegetables. Added sugars Sugars added to foods during processing or preparation (e.g. mono- and disaccharides as well as naturally occurring sugars that are isolated from a whole food and concentrated so that sugar is the primary component, such as fruit juice); excluding naturally occurring sugars present in intact fruit, vegetables or dairy products or in juiced or puréed fruit and vegetables. Measurement of sugar content There are a variety of tests that can be performed to determine sugars content in food, animal feed and pharmaceutical products. These tests may be non-specific (total sugars) or specific (individual mono-, di- and polysaccharides). The classic test for simple carbohydrates is the Benedict's test. This test can be used to identify reducing sugars (mono- and some disaccharides) thanks to the interaction of the free ketone or aldehyde group from the reducing sugar with copper ions (Figure 3). The term ‘reducing sugars’ refers to the capability of some sugars (typically monosaccharides, like glucose) to transfer electrons to other compounds through reduction. In the simplest form of the test, reducing the copper ions from divalent to monovalent forms produces a colour change and precipitation. Depending on the test protocol used, the colour change may be interpreted as a qualitative or quantitative measure of the concentration of reducing sugars. It is generally necessary to perform additional preparation of samples prior to Benedict's test: extraction for any solid samples and acidification for all samples to ensure sugars are converted to reducing sugars. However, the copper-reduction reaction is not specific to reducing sugars. Therefore, its use as a measure of total sugars depends upon their concentration relative to other compounds that can be reduced. Methods that use the copper-reduction reaction commonly used in the sugar industry include the Lane and Eynon Constant Volume Procedure, Knight and Allen and Luff Schoorl. Figure 3Open in figure viewerPowerPoint Copper reduction reaction for reducing sugars Other methods for determination of sugars include: Colorimetric methods, Enzymatic methods Chromatographic methods: Colorimetric methods tend to be non-specific but applicable to most carbohydrates and used when a very small concentration of carbohydrate is present. Enzymatic methods tend to be used for determination of select individual sugars and there are specific test kits as well as biosensors available for use in testing (e.g. blood glucose determination). Chromatographic methods tend to be used for identification and measurement of individual sugars and have the widest application in research and commercial laboratories. Although chromatographic methods can offer a more accurate measurement of individual sugars, care must be taken as not all analyses performed by testing laboratories are as specific as one may require. An example of this is that some High Pressure Liquid Chromatography (HPLC) columns in use for routine testing of carbohydrates are suitable only if the specific sugars are known, as the separation of the sugars is often more in terms of size/shape than for all typical individual sugars. The most common simple HPLC analysis of sugars uses an aqueous ion-exchange separation, wherein polysaccharides (specifically sugars of four or more monosaccharide units), trisaccharides, disaccharides and certain monosaccharides are separated and determined using a refractive index detector (see Figure 4). It is not advisable to use this type of analysis if one needs to determine all the different sugars present in a given sample without knowing exactly which are there (e.g. the standard ion-exchange HPLC columns often are unable to separate sucrose from maltose and some other compounds, like proteins, can be mis-identified as sucrose when using such a column). Figure 4Open in figure viewerPowerPoint Intensity of sweetness perceived over time, for sucrose, acesulphame K (AceK) and aspartame. Unlike with the specified regulations for sugar product (as shown for white sugar in Table 1), there are no standardised or agreed tests for determination of free and added sugars. As already described, there are a variety of options to determine the sugars content in foods. However, there is no agreed process to definitively assess what proportion of the total sugars present are naturally occurring in the food versus sugars that are added (e.g. fruit naturally contains sugars but jam contains both the sugars from the fruit and additional sucrose). Examples of how estimations may be made include assessment of individual components of a recipe, calculation from national food composition databases or complicated separation of components with estimation of typical end-product mastication results[9-11]. Regardless of the current methods in use, there is a need to have an agreed universal method to quantify free or added sugars relative to naturally present sugars so the nutritional effect of these extra sugars can be better understood. Additionally, better understanding of free or added sugars relative to natural sugars is essential for effective reformulation to lower sugars content. Sugar is a multi-functional ingredient, so replacement is not just about sweetness Sugars have many functional properties other than providing sweetness. The main additional functional properties are structure, colour, flavour and preservative. Structure can be further differentiated into mouthfeel, bulk and humectancy. All these properties must be considered when reformulating to replace, remove or reduce sugars from processed foods and may be why it can be challenging to replace sugars. With respect to structural properties, particle size and behaviour of the sugar molecules themselves produce results that are desirable in both sensory and, shelf-life terms. Sugars are readily dissolvable and in the right concentrations, can act as a preservative as well as affect the freezing point of some food products. The colour and flavour of food products can be altered by the reaction of sugars with the other ingredients present via the Maillard reaction and/or caramelisation. Additionally, although sweetness intensity is described relative to the sweetness of sucrose (see Table 3 for comparison of typical sweeteners), the latter has also a time-intensity profile that needs to be part of the reformulation consideration (see Figure 4) Table 3. Comparison of typical EU-approved sweeteners[5] relative to sucrose Sugars Intense sweeteners Bulk sweeteners Sweetener Sweetness Sweetener Sweetness Sweetener Sweetness Fructose 1.2x Acesulfame-K 200x Sorbitol 0.6x Glucose 0.7x Aspartame 200x Mannitol 0.5x Sucrose 1.0x Saccharin 300-500x Isomalt 0.4x Trehalose 0.5x Sucralose 600-650x Maltitols 0.9x Tagatose 0.9x Steviol Glycosides 200-300x Xylitol 0.9-1.0x Iso-maltulose 0.5x Thaumatin 2000-3000x Erythritol 0.6-0.7x The main driver for replacement of sugars in food products globally is a reduction in calories. However, the calories in a product are not only due to the presence of sugars and other ingredients like protein, fat and alcohol will also contribute. Some products are relatively easy to reformulate such as Soft Drinks where the bulk of the sugars present can be replaced with water and the sweetness in the product can be provide by high intensity sweeteners. In products with a low water content and/or high levels of fat and sugars the challenge to reduce the amount of sugars and deliver a significant calorie reduction is more complicated. Sugar (in terms of carbohydrate content) is 4 calories/g, whereas many alternative sweeteners are lower or have no calorific value; however, on the other hand, they might have few or none of the other functional properties provided by sugars. Most of the calories found in the majority of food products are not just due to sugar. Fat, protein, and alcohol all have calorific contents, so the proportion of the other ingredients relative to the sugar being replaced is significant. Some food products are relatively easy to reformulate, like soft drinks, where the bulk of the sugars is replaced with water, and high-intensity sweeteners provide the sweetness. In products with low water content and/ or high levels of fat and sugars, the challenge of reformulation providing a significant reduction in calories is more complicated. Other drivers for reformulation include development of ‘functional’ products, innovation for new products, and provision of choice for consumers. Regardless of the drivers for reformulation, it is necessary to consider more widely how to best to approach reformulation specific to the product. A sophisticated approach to reformulation should be an understanding of what ingredients provide for a product and how the same taste characteristics can be provided with a reduction in calories and increase in satiety and an overall healthier product. Examples of some alternative sweeteners are shown in Table 3, but there are other alternatives that aren't yet approved in the EU, such as monkfruit and brazzein. These sweeteners may be commercially appealing, due to their having natural origins, from plants and berries, as opposed to artificial sweeteners. However, use of alternative sweeteners will require increased labelling, likely in terms of more ingredients but also E-numbers and possibly warnings. The continuous change in consumer attitudes is something any food producer needs to be keenly aware of. Although artificial sweeteners have been around for a long time (with saccharin being developed in 1878; Ace-K and aspartame developed in 1967), consumers continue to have concerns regarding safety of any artificially developed food additive. It is possible that alternatives that are derived from other foods through fermentation, bioconversion and enzymatic production, like allulose, may be more acceptable to consumers. Even if there is no single alternative, it may be better to blend a number of different alternative sweeteners than to use a single sweetener, in terms of sweetness as well as other functional attributes. Some alternative sweeteners can provide more functionality than just sweetening. Polyols (such as sorbitol and xylitol) can provide texture, structure and humectancy however some have alternative functional properties: xylitol has a pronounced cooling effect which works well in mint-based products but does not work in all applications. In addition, some of the polyols, like xylitol, do have some desirable functional benefits (some of them being cariostatic properties, therefore contrasting dental caries). Some of the newer sweetener alternatives also provide more than just sweetness. Work that has been done on so-called ‘upcycled’ sweeteners has resulted in products that provide structure functionality due to residual fibre content. In general, to fulfil the structural, colour, flavour and preservative functions that sugar has, reformulation will require a significant amount of ingredients. Thus, replacement of sugar in a processed food product could require addition of bulking agents, flavours, colours, preservatives without producing a product that meets customer expectations, even if it is fit for purpose otherwise. The challenges for the food product developer with respect to why reformulation is required are as follows, and they are also interlinked to each other: Regulations (labelling, additives use, health and nutrition claims); Regulators (local/country requirements, industry levies, public health guidance); Shareholders (brand protection, innovation, sales vs cost); Consumers (reduced calories, recognisable ingredients, choice and value, taste). Regardless of the technical nature of the reformulation required, there will be restrictions to what can be done to achieve reformulation that meets the challenges listed above. Labelling is not globally defined so any food producer attempting to reformulate, remove or reduce sugar in a product will have to maintain knowledge of allowed alternatives, levels thereof and similar, to determine the viability of any product to be reformulated. Shareholders rarely understand the nuances of product development, so a clear plan for reformulation must indicate the drivers and possible inhibitors to the process, all relative to cost. However perfect the design for reformulation may be, it won't work unless it meets customer expectations. A paradigm shift is required if reformulation is going to deliver all the attributes required, like: reduced sugars, reduced calories, improved nutrition, consumer acceptance and value to the consumer and shareholder. A focus on simple substitution is unlikely to deliver all of these requirements and the use of other ingredients such as fibre to deliver reduced calories, functional benefits and increased satiety will be required to deliver the foods of tomorrow. The complexity in pursuing reformulation may be the same, whatever the approach, but development of a new product, as opposed to simply updating an existing one, may provide scope for brand extension and sustainability recognition, particularly through use of ‘upcycled’ natural products. Both could help engage shareholders and consumers as well as possibly help influence changes in regulations and how regulators define guidance. Conclusion Sugars are recognised as natural, traditional and globally defined ingredients that are also multifunctional in terms of their use in food products. The information provided to the public about the need to reduce sugars consumption may result in increased use of low or non-calorific sweeteners, but there are still concerns about negative side effects from such sweeteners, including flavour profile and adverse reactions (one being potential laxative effects). Additionally, labelling foods as ‘no added sugar’ may be perceived as healthier, even if alternative (non-sugar) sweeteners have been added. The availability of reduced and no-added sugars products may also have unintended consequences – if there is little or no reduction in calories the ‘halo effect’ of the claims may also promote over consumption of the reformulated products. Replacement of sugars to reduce calorific content in processed food products is not simple, due to both the functionality of sugars and effect of other calorific ingredients (like fats) within the conventional product. The presumptions that sugars can be directly replaced with alternative sweeteners and yet meet the demands of industry, legislation and consumers is flawed. Considerably more work is needed to define suitable alternatives that meet not just the calorific reduction but also provide the functionality, cost, taste and sustainability requirements of both producers and consumers. The gold standard for reformulation should be to produce a healthy, sustainable, low-or equivalent cost product that is as palatable and better than the current offering. Julian Cooper and company Karen Pardoe Julian Cooper is a carbohydrate chemist with more than 40 years’ experience in the food industry. He is a visiting professor at the University of Reading and a former chair of the scientific committee at IFST. He retired from Associated British Foods (British Sugar) in 2015 and is now an independent consultant to the food industry. email jmcooper342consulting@gmail.com Karen Pardoe is an analytical chemist with more than 30 years’ experience, primarily in the food industry. She is a member of a variety committees relating to chemistry and food, including the Food Science and Technology Advisory Panel of the IFST. She left Associated British Foods in 2021 and is also an independent consultant. email karen.pardoe@kpsconsultingltd.com References 1 Institute of Food Science and Technology. 2022. Sugars. Available from: https://www.ifst.org/resources/information-statements/sugars 2 US Food and Drug Administration. 2018. Letter to Ms. Pelonis Re: GRAS Notice No. GRN 000812. Available from: https://www.fda.gov/media/130891/download 3 The National Archives. 2020. Council Directive 2001/111/EC of 20 December 2001 relating to certain sugars intended for human consumption. Available from: https://www.legislation.gov.uk/eudr/2001/111 4 The National Archives. 2013. Regulation (EU) No 1308/2013 of the European Parliament and of the Council. Available from: https://www.legislation.gov.uk/eur/2013/1308/contents 5 The National Archives. 2003. The Specified Sugar Products (England) Regulations 2003. Available from: https://www.legislation.gov.uk/uksi/2003/1563/contents/made 6 Food and Agriculture Organization of the United Nations. 2001. Codex Standard for Sugars, CODEX STAN 212-199, Amendment 2001. Available from: https://www.fao.org/input/download/standards/338/CXS_212e_u.pdf 7 Public Health England. 2015. SACN Carbohydrates and Health Report. Available from: https://www.gov.uk/government/publications/sacn-carbohydrates-and-health-report 8McGuire, S. 2016. Scientific Report of the 2015 Dietary Guidelines Advisory Committee. Washington, DC: US Departments of Agriculture and Health and Human Services, 2015. Advances in Nutrition 7: 202- 204. Available from: https://pubmed.ncbi.nlm.nih.gov/26773024/ 9Azaïs-Braesco, V., Sluik, D., Maillot, D., Kok, F., Moreno, L. A. 2017. A review of total & added sugar intakes and dietary sources in Europe. Nutrition Journal 16: 6. Available from: https://nutritionj.biomedcentral.com/articles/10.1186/s12937-016-0225-2 10Mela, D. J., Woolner, E. M. 2018. Perspective: Total, Added, or Free? What Kind of Sugars Should We Be Talking About? Advanced Nutrition 9: 63- 69. Available from https://academic.oup.com/advances/article/9/2/63/4969263 11Mela, D. J. 2020. A proposed simple method for objectively quantifying free sugars in foods and beverages. European Journal of Clinical Nutrition 74: 1366- 1368. Available from: https://www.nature.com/articles/s41430-020-0575-x Volume37, Issue1March 2023Pages 26-31 FiguresReferencesRelatedInformation