Offal contains an increased vitamin D concentration compared to lean meat^{(Reference Schmid and Walther1)} and therefore, as an ingredient, may be an innovative strategy to enrich the vitamin D content of meat products to help address hypovitaminosis D reported globally^{(Reference Cashman2)}. However, it is essential that changes in sensory characteristics are minimised to ensure consumer acceptability^{(Reference Buttriss and Lanham-New3)}. This study aimed to 1) investigate vitamin D-enrichment of various pork offal concentrations (0- 40%) on the vitamin D content of pork sausages, and; 2) to determine sensory acceptability and consumer perceptions of vitamin D-enriched pork sausages compared to control.

Sausages were vitamin D-enriched with various concentrations (5%, 10%, 20%, 30% and 40%) of pork offal (heart, liver and kidney; approx. 33% each) or control (0%). Vitamin D3and 25(OH)D3 (μg/kg), were analysed in cooked offal and sausage samples by LC-MS/MS^{(Reference Neill, Gill and McDonald4)}. Vitamin D activity was calculated as: [vitamin D3 + (25(OH)D3 x 5)]^{(Reference Cashman5)}. Sausages were developed from sausage meat, seasoning blend, rusk, water and casing, and frozen prior to sensory evaluation. Consenting adults (n = 50) aged 18–65 years were recruited. Sausages were oven roasted (180°C) until an internal temperature of >75°C was reached. Participants were presented with a trio of sausages (n = 1 vitamin D-enriched; n = 2 control) each randomized by a three-digit code, in an ascending series threshold test, based on the 3-AFC method^{(Reference Mojet, Christ-Hazelhof and Heidema6)}. Detection and recognition values were determined by best estimate threshold, calculated by geometric mean of the highest offal concentration missed and the next highest offal concentration (%)^{(Reference M Meilgaard, Civille and Carr7)}. Where participants recognised the sample that was different, they were asked to qualitatively describe the difference. Qualitative results were coded, categorised into themes and presented as frequency of participants (%) for each of the offal sausages (5–40%).

Theoretical vitamin D-enrichment of sausages resulted in a significant increase in mean ± SD vitamin D activity at 20% (17.0 ± 0.7 μg/kg), 30% (19.0 ± 1.0 μg/kg) and 40% (20.9 ± 1.4 μg/kg) offal compared to control (13.2 ± 0.3 μg/kg); P < 0.05. Sensory evaluation revealed that 40% of participants detected the vitamin D-enriched sausage (5% offal) and 23% of participants recognised the vitamin D-enriched sausage (5% and 7.1% offal). Eight themes were identified from the qualitative responses (seasoned, stronger flavour, harder texture, disliked taste, unidentified, meaty flavour, softer texture and liked taste). Participants reporting disliked taste (22%) and stronger flavour (22%) were greater at 20% compared to 5% offal concentration (4% and 12% respectively).

In conclusion, theoretical vitamin D-enrichment (20–40% pork offal) significantly increased vitamin D activity in cooked sausages. Preliminary sensory analysis indicates that consumers are aware of the difference with 5–7.1% offal concentration incorporated and may report the product as unacceptable. Further sensory evaluation, ideally with qualitative research, is required to confirm these results in a larger population group.