CLSM method for the dynamic observation of pH change within polymer matrices for oral delivery

If acid-sensitive drugs or cells are administered orally, there is often a reduction in efficacy associated with gastric passage. Formulation into a polymer matrix is a potential method to improve their stability. The visualization of pH within these materials may help better understand the action of these polymer systems and allow comparison of different formulations. We herein describe the development of a novel confocal laser-scanning microscopy (CLSM) method for visualizing pH changes within polymer matrices and demonstrate its applicability to an enteric formulation based on chitosan-coated alginate gels. The system in question is first shown to protect an acid-sensitive bacterial strain to low pH, before being studied by our technique. Prior to this study, it has been claimed that protection by these materials is a result of buffering, but this has not been demonstrated. The visualization of pH within these matrices during exposure to a pH 2.0 simulated gastric solution showed an encroachment of acid from the periphery of the capsule, and a persistence of pHs above 2.0 within the matrix. This implies that the protective effect of the alginate-chitosan matrices is most likely due to a combination of buffering of acid as it enters the polymer matrix and the slowing of acid penetration

Formation and Degradation of Beta-casomorphins in Dairy Processing

Milk proteins including casein are sources of peptides with bioactivity. One of these peptides is beta-casomorphin (BCM) which belongs to a group of opioid peptides formed from b-casein variants. Beta-casomorphin 7 (BCM7) has been demonstrated to be enzymatically released from the A1 or B b-casein variant. Epidemiological evidence suggests the peptide BCM 7 is a risk factor for development of human diseases, including increased risk of type 1 diabetes and cardiovascular diseases but this has not been thoroughly substantiated by research studies. High performance liquid chromatography coupled to UV-Vis and mass spectrometry detection as well as enzyme–linked immunosorbent assay (ELISA) has been used to analyze BCMs in dairy products. BCMs have been detected in raw cow’s milk and human milk and a variety of commercial cheeses, but their presence has yet to be confirmed in commercial yoghurts. The finding that BCMs are present in cheese suggests they could also form in yoghurt, but be degraded during yoghurt processing. Whether BCMs do form in yoghurt and the amount of BCM forming or degrading at different processing steps needs further investigation and possibly will depend on the heat treatment and fermentation process used, but it remains an intriguing unknown

Fresh-cut vegetables

This chapter reviews various aspects of fresh‐cut vegetables, including sensory, physiological, microbial, and manufacturing details. To obtain fresh‐cut vegetables, the basic premise is minimal processing to retain fresh like texture, color, and flavor, and safe‐to‐use quality. This chapter illustrates the normal processing steps for fresh‐cut vegetables. Wounding or injury associated with processing and handling fresh‐cut vegetables can cause physiological changes, which influence ethylene production, respiration rate, discoloration, deterioration of texture, and water loss. Good manufacturing practice (GMP) and Hazard Analysis and Critical Control Points (HACCP) based production and handling, and proper documentations related to sourcing, processing, quality checking, packaging, and storage are important to ensure the safety and traceability of fresh‐cut vegetables. There are many physical methods that have been researched to reduce the microbial load in fresh‐cut vegetables, including modified atmosphere packaging (MAP), ultraviolet (UV) light, irradiation, high‐pressure processing, and ultrasonics. Among these techniques, MAP has been widely used commercially

Properties and applications of different probiotic delivery systems

Probiotic products should contain and maintain viable cells during the product shelf life at least above therapeutic minimum level for the benefit of consumers. Due to their generally poor viability and stability in food products, especially in fermented dairy products, as well as in the host gastrointestinal tract, various microencapsulation techniques for probiotics have been developed in recent years to overcome these issues. This chapter describes the benefit of microencapsulation, various encapsulation techniques used to encapsulate probiotics and the application of encapsulated probiotics in selected food systems. The use of various supporting or encapsulating materials, such as alginate, chitosan and carrageenan is also discussed. Special treatments (such as complexation coating) of capsules for further improving the stability of the probiotics are also described