Submaxillary mucin is a major component that defines the makeup and functionality of saliva. Understanding its structure and function during food intake is key to designing appropriate strategies for enhancing the delivery of flavour. In the present study, the hydrodynamic integrity of bovine submaxillary mucin was characterised under physiological and acidic conditions and it was shown to have a broad molecular weight distribution with species ranging from 100 kDa to over 2000 kDa, and a random coil type of conformation. A decrease in the pH of mucin appeared to result in aggregation and a broader molecular weight distribution, which was shown to correlate with a release of flavour compounds. Our study also provides indications that p -cresol may have an effect on the macromolecular integrity of mucin.

Flavoured potato crisps is the UK's most consumed snack food product. Addition of N2 gas flushing extended shelf life by 2 weeks and the addition of seasoning further enhanced the shelf life of the base crisps by 2 weeks under accelerated conditions.

29Metallic taints elicited when consuming food can be unpleasant for the consumer, and are 30 therefore problematic to food manufacturers. Although metallic has been proposed as a taste in the 31 past, evidence remains inconclusive. This study investigates the oral and nasal contributions to 32 metallic perception using sensory evaluation and headspace analysis using gas chromatography mass 33 spectrometry (GC-MS). When sniffing the headspace over divalent salt solutions some were 34 discriminated from water. GC-MS did not detect volatiles in the sample headspace, one hypothesis 35 being that sample volatiles react with phospholipids in the nasal cavity and it is lipid oxidation 36 products which are perceived. Copper sulphate was reported as metallic when tasted with the nose 37 occluded to eliminate retronasal perception, suggesting a gustatory or trigeminal mechanism may be 38involved. This work indicates orthonasal stimulation is involved in metallic perception, and 39 contributes to the ongoing debate over metallic being a taste, trigeminal or flavour response. 40 41

To reduce animal testing, there is a need to develop novel in-vitro models for evaluating the retention of bioactive compounds in food and pharmaceutical products. Here, a mucus-mimetic platform was developed through a one-step approach based on encapsulating mucin within alginate gel beads. We found that mucins form micron sized aggregates distributed across the surface of the calcium-alginate bead, as shown by environmental scanning electron microscopy (ESEM). Retention of bioactive compounds on the mucin-functionalised surface was tested using a commercial orange drink formulation. To aid flavour retention, different mucoadhesive polymers with varying charge, including anionic, neutral and strongly cationic, were tested for their ability to interact with mucin and aid retaining flavour compounds within the mucin-alginate bead. The alginate-mucin mucus mimic was validated using an ex-vivo bovine tongue, with the flavour retention results showing qualitative agreement. The developed method proved to be a convenient, efficient tool for providing information on the effectiveness of mucoadhesive polymers without variability, safety and sustainability issues associated with an ex-vivo or in-vivo system. We propose that by encapsulating other relevant oral proteins, alongside mucins, current gaps between in-vitro and the ex-vivo systems may be narrowed.

While a good mucoadhesive biopolymer must adhere to a mucus membrane, it must also have a good unloading ability. Here, we demonstrate that the biopolymer pullulan is partially digested by human salivary α-amylase, thus acting as a controlled release system, in which the enzyme triggers an increased release of flavour. Our oral processing simulations have confirmed an increase in the bioavailability of aroma and salt compounds as a function of oral pullulan degradation, although the release kinetics suggest a rather slow process. One of the greatest challenges in flavour science is to retain and rapidly unload the bioactive aroma and taste compounds in the oral cavity before they are ingested. By developing a cationic pullulan analogue we have, in theory, addressed the “loss through ingestion” issue by facilitating the adhesion of the modified polymer to the oral mucus, to retain more of the flavour in the oral cavity. Dimethylaminoethyl pullulan (DMAE-pullulan) was synthesised for the first time, and shown to bind submaxillary mucin, while still retaining its susceptibility to α-amylase hydrolysis. Although DMAE-pullulan is not currently food grade, we suggest that the synthesis of a sustainable food grade alternative would be a next generation mucoadhesive targeted for the oral cavity.