Digestion is a complex process involving various enzymatic processes and conditions. Digestion is important as food is broken down into nutrients, which the body uses for energy, growth, and cell repair. An in-vitro digestion model has been develop to provide a representative assessment of the digestion processes for food and pharmaceuticals. This model considers the important features of the digestion processes such as the digestive enzymes and their concentrations, pH, digestion time and salt concentrations. The model has been validated by scientists and researchers from AgResearch in New Zealand. In comparison with human clinical study or animal model, the in vitro digestion is normally faster, less expensive and less resource intensive.
• In vitro gastro-intestinal (GI) digestion normally contains oral, gastric and (small) intestinal phases. The system is based on an international agreed procedure.
• A temperature of 37C is typically used in all in vitro digestion, mimicking the temperature in human body. The most common biological materials used in an in vitro digestion model are digestive enzymes (pancreatin, pepsin, trypsin, chymotrypsin, peptidase, α-amylase, and lipase), and bile salts.
• Dependent on the adult/young child/infant (GI) digestion model, different types and concentration of the enzymes can be used. The digestion/transit time and pH at each GI phase is varied depending on whether the infant or adult model is used.
The in vitro digestion model can be used for a wide range of applications. Some of the key applications are:
• To predict or model the digestion kinetics of foods/food components, pharmaceutical/therapeutic substances.
• To determine the digestibility and bio-accessibility of pharmaceuticals, mycotoxins, and macronutrients such as proteins, carbohydrates and lipids.
• To track down the structural and chemical changes of food or food-based/lipid-based drug delivery systems under the human physiological conditions.
• To investigate the release of peptides and bioactive compounds following digestion process of foods and food components (e.g. protein, lipid, carbohydrate).
• To investigate the release of micronutrients such as, amino acids, fatty acids, minerals, vitamins and secondary plant compounds (e.g. carotenoids, polyphenols).
• To produce bio-accessible fractions that can be used to investigate health efficacy of food and ingredient, such as intestinal transport by employing Caco-2 cells, and immunological responses.
• The in vitro digestion model allows rapid assessment of a large quantity of samples at an early stage of production innovation when the target product format is largely unknown.
• Consumers are now more knowledgeable about the food products that they are eating and tend to favour foods with potential health benefit effects such as improved digestibility and increased bioavailability of bioactive components.
• These customers’ demands serve as the basic driving force for food manufactures/ pharmaceutical producers to seek for useful tools to assess the behaviours of food/food- based drug delivery system upon digestion.
• The in vitro digestion model is of special interest for the food/pharmaceutical stakeholders, especially those who are working on formulation and development of healthier food products, foods with improved digestibility/increased bioavailability of bioactive components.
• The in vitro digestion models are relative rapid, and cost effective without the ethical issues associated with animal or human studies.
• They are useful tools to increase the understanding about the different behaviour of different foods/food-based drug delivery systems in the human gut, the mechanism and kinetics related to the degradation of targeted nutrients/components and tracking down their structural changes during the GI digestion.