Adding value to under-utilised Irish fish roe: a physico-chemical and sensory comparison of cured Irish pollock (Pollachius pollachius) roe with commercial mullet (Mugil cephalus) and cod (Gadus morhua) products

Abstract

Irish marine fish roe is generally discarded at sea or processed as low value-added fishmeal and not utilised as nutritious seafood ingredients. Locally sourced pollock roes were salted, air-dried (Mediterranean-style) and compared to similar commercial mullet and cod products for: weight; moisture content; pH; instrumental texture and colour; and sensory attributes. Raw pollock roes averaged 105 g (n = 25). Roes lost on average 3.1% moisture (w/w) after a 2-h salting period and 48.8% weight reduction was observed after an average 105 h air-drying time. The moisture content of pollock was not significantly different to commercial products. Average pH for pollock, mullet and cod products was 5.9, 5.4 and 5.7, respectively (P < 0.05). Pollock and mullet had similar hardness, but cod was significantly harder than both, when measured instrumentally. Total colour difference (ΔE*) between the surface of pollock and cod, and that of pollock and mullet was 7.5 and 3.0, respectively. Sensory assessment of sliced and powdered products, using 9-point hedonic and 5-point just-about-right (JAR) scales, was conducted with 38 consumers. Pollock received the highest scores for overall liking and intention to purchase compared to commercial mullet and cod products, averaging 5.6, 5.6 and 4.9, respectively, for sliced roe products, and 6.3, 5.3 and 6.1 for powdered products. Penalty analysis of JAR showed “overall liking” was impacted by the flavour being “too fishy”. In conclusion, pollock had similar characteristics and acceptable sensory attributes compared to commercial products presenting opportunities to expand the range of value-added roe products (e.g., trout, salmon) available, while also contributing to waste reduction.