Unlocking Bioavailability: Elevating Food Quality Through Smart Processing

Abstract

Shalima Sreenath explores how food processing affects bioavailability of bioactive compounds in functional foods, and how it also impacts overall food quality. By focusing on methods like fermentation, encapsulation, and thermal processing, it shows how processing can improve nutrient absorption while maintaining or enhancing the quality, flavour, and texture of food.

In recent years, the concept of food as medicine has emerged as a transformative force in the realm of nutrition, combining ancient wisdom with cutting-edge science to redefine our approach to health. While its roots trace back to early civilizations that recognised the healing potential of food, today's renewed interest is fueled by mounting evidence linking diet to chronic diseases such as diabetes, cardiovascular disease, and obesity. Advances in nutritional science, coupled with the rise of functional foods and personalised nutrition, are driving this movement forward in the 21st century. This evolution signifies a shift towards holistic, preventative healthcare, where the role of food is not just to nourish but to actively promote health and well-being.

When evaluating the health benefits of functional foods, a key factor to consider is their bioavailability, which refers to the proportion of of bioactive compounds absorded and utilised by the body after consumption. Bioavailability determines how effectively these beneficial compounds are delivered to target tissues to exert their desired health effects.

When it comes to food-related factors, food processing plays a major, if not the most important role in influencing bioavailability. Processing methods can significantly influence nearly all food-related aspects of bioavailability. This is especially important for functional foods since these are consumed with the greater purpose of tapping the benefits beyond day-to-day nutrition. From the moment raw materials are harvested, through to storage, preparation, and cooking, each stage in the food production journey can either preserve, enhance, or degrade the nutritional value of the final product. For these foods to deliver their promised benefits, it is essential that processing methods are carefully selected and optimised.

Thermal processing is one of the most common food processing methods used for extending shelf-life, improving safety by eliminating pathogens. It is also chosen for its ability to alter texture, making foods more palatable and easier to digest. Thermal processing includes methods like boiling, steaming, roasting, and pasteurization, and can either enhance or degrade nutrient bioavailability, depending on the nutrient.

An example of the impact of thermal processing on bioactive compounds is the processing of tomatoes, where the bioavailability of lycopene is positively impacted. Lycopene is a carotenoid and a powerful antioxidant that has been associated with various health benefits, such as reducing the risk of certain cancers and promoting heart health. When tomatoes are processed through methods like canning, cooking, or heat treatment, the heat causes a breakdown of the tomato's cellular structure which releases lycopene from the plant matrix, making it easier for the body to absorb and utilise. In fact, the bioavailability of lycopene is significantly higher in cooked or processed tomatoes compared to raw ones. While some water-soluble vitamins, like vitamin C, may degrade during processing, the overall improvement in lycopene bioavailability outweighs this for many people.

Fermentation is a biological process that uses microorganisms like bacteria, yeast, or fungi to break down food components, often improving nutrient bioavailability. It can also promote the production of beneficial probiotics, which support gut health. Fermentation is widely used in the production of functional foods like yogurt, kimchi, and kefir, where improved nutrient absorption is a key benefit. A classic example is the effect of fermentation on oats. Fermentation significantly enhances the bioavailability of nutrients by breaking down anti-nutrients naturally present in oats such as phytates that can inhibit the absorption of essential minerals like iron, calcium and zinc. Tannins, which can hinder protein digestibility and block the absorption of minerals, are also broken down. During fermentation, beneficial microorganisms, such as lactic acid bacteria, release enzymes that degrade phytates, making minerals more accessible for absorption in the digestive tract. The process of fermentation also enhances the digestibility of oats, as the microorganisms partially break down fibers, making the nutrients more easily absorbed by the body. As a result, fermented oats not only offer improved nutritional value but also support better digestive and immune function.

Fermented foods are rooted in the culture and heritage of various ethnic communities. They are integral to the local diets and cultures of their respective regions and research indicates that ethnic fermented foods such as kimchi and others have beneficial effects on health in addition to providing rich flavours. There is a significant need of preserving traditional processing methods on these foods, which face the threat of extinction due to urbanisation and shifting dietary preferences. The enhanced bioavailability of nutrients in these foods further highlights their value and the need for safeguarding these practices.

Mechanical processing methods like milling and grinding reduce the particle size of food, which can increase the surface area available for digestion and absorption. This is particularly important for grains, where the outer bran layer contains fiber that may inhibit nutrient absorption. Milling removes or breaks down this layer, enhancing the bioavailability of certain vitamins, minerals, and phytochemicals. However, excessive refining can also remove valuable components like fibre and essential fatty acids, so the extent of milling needs to be carefully controlled.

Encapsulation is a technique used to protect sensitive bioactive compounds, such as omega-3 fatty acids, probiotics, or polyphenols, by enclosing them within a protective coating. This method helps improve the stability and bioavailability of these compounds, preventing their degradation during processing, storage, and digestion. Encapsulation can enhance the absorption of nutrients in the body, ensuring that functional ingredients retain their potency until they are effectively released in the digestive system.

Drying in food processing inhibits microbial growth, extends shelf-life, and reduces food weight for easier transport. Spray drying turns liquid mixtures into powders by rapidly drying them using hot air and is commonly used for functional ingredients like protein and vitamins. While heat can reduce the bioavailability of some sensitive nutrients, controlled temperatures help preserve nutrient content and improve bioavailability by breaking down food into fine particles that are more easily absorbed. Low-temperature methods, like vacuum or freeze drying, better maintain sensitive nutrients such as vitamins and antioxidants. For instance, drying fruits like blueberries at low temperatures preserves antioxidants while enhancing flavour and texture. These techniques ensure bioactive compounds remain effective, making dried foods both nutritious and appealing to consumers.

Extraction is a targeted food processing method that isolates specific bioactive compounds from raw materials, increasing their concentration and bioavailability. Common methods like solvent extraction, cold pressing, and supercritical fluid extraction help obtain essential oils, vitamins, and antioxidants from fruits, vegetables, and herbs. Extraction enhances bioavailability by removing compounds that inhibit nutrient absorption, such as anti-nutrients and fibre. For example, the extraction of curcumin from turmeric can concentrate this potent anti-inflammatory compound, making it more readily absorbed by the body when used in supplements or functional foods. However, the extraction process must be carefully controlled, as excessive use of solvents or high temperatures can lead to the degradation of sensitive nutrients.

Formulation in food processing refers to the strategic combination of various ingredients and processing techniques to create food products that maximise nutritional benefits and improve bioavailability by incorporating various blending technologies in the market. By blending bioactive compounds from sources like fruits, vegetables, grains, and proteins, manufacturers optimise nutrient composition and manage interactions that affect absorption. For example, pairing vitamin C-rich fruits with iron enhances non-heme iron absorption. Specific emulsifiers or stabilisers can improve the solubility of fat-soluble vitamins, aiding their absorption. Additionally, incorporating prebiotics or probiotics supports gut health, further enhancing nutrient uptake. Overall, formulation ensures bioactive components work together to provide optimal health benefits.

Packaging plays a crucial role for preserving the bioavailability of functional foods by shielding them from environmental factors like light, oxygen, moisture, and temperature, which can degrade nutrients. For example, opaque or vacuum-sealed packaging helps reducing oxidation of sensitive compounds like vitamins and antioxidants, while moisture-proof designs prevent microbial growth that could compromise nutrient integrity. However, inappropriate packaging materials may leach harmful substances, affecting nutrient bioavailability or introducing toxins. Therefore, selecting the right packaging is crucial to maintain the health benefits of functional foods.

Future trends in functional ingredients are set to be revolutionised by advanced technologies like precision fermentation, which enables the production of bioactive compounds sustainably and efficiently while also improving bioavailability. Using genetically engineered microbes, precision fermentation creates specific, pure bioactives such as proteins, vitamins, and peptides, optimised for better absorption and stability. This technology reduces environmental impact by eliminating traditional agriculture and allows for precise engineering of bioactives tailored to health needs. As demand for plant-based and personalised nutrition grows, precision fermentation will transform bioactive production for better health outcomes.

Food manufacturers and process development professionals must, therefore, give serious consideration to each step in the production process—from the choice of raw materials, through to drying, milling, fermentation, and even packaging. Techniques that minimise nutrient loss or promote nutrient bioavailability, such as minimal thermal processing, controlled fermentation, or encapsulation technologies, should be prioritised. ‘When factors like heat, processing times, water quality, and processing aids impact product functionality, it's imperative to study their impact on bioavailability and set optimal processing ranges. This is where pilot trials play a key role in quickly and cost-effectively identifying potential issues before a product is commercialized into manufacturing’ - says Manish Shrivastava, Head of Engineering at Nuritas, a company which uses artificial intelligence to discover and develop bioactive peptides from plants for health and wellness products. ’Ensuring the desired bioavailability in commercial production of functional foods is a fascinating challenge that can be overcome by a carefully planned scale-up process, an effective in-process testing regime, and clear manufacturing instructions’, Manish mentions, as he talks about how the impact on bioavailability is always in the back of his mind as he works with different manufacturing facilities to commercialise processes from laboratory testing to production.

Despite the negative perception surrounding processed foods, food processing and processed foods are not inherently negative; in many cases, they offer significant benefits, especially in the realm of functional foods. The overarching goal is to ensure that the processing methods do not just retain, but ideally enhance the bioavailability of key nutrients and functional ingredients, allowing consumers to gain the maximum health benefits from the foods they eat. By doing so, food companies can offer products that are not only convenient and shelf-stable but also nutritionally superior, meeting the growing consumer demand for foods that promote wellness and support a healthy lifestyle. Additionally, processing can contribute to sustainability efforts by reducing food waste and ensuring that only the most beneficial components are included while excluding non-nutritive elements. By fostering a better understanding of food processing, consumers can appreciate the value of functional foods and incorporate them effectively into their diets.