2.2. Consumer Sensory Evaluation

One hundred and sixty consumers were recruited in Dunedin (New Zealand) in June 2018 to quantify the overall liking, flavor liking, tenderness and juiciness of the six lamb types and to determine the willingness to pay across four conceptual levels of lamb quality [17,18]. Vacuum-packed loin sections (approximately 15 cm) were thawed at 4 °C for 24 h and then cooked using sous vide at 57 °C for 1 h. After cooking, the loins were removed from the sous vide bag, dried using paper towels and rested at room temperature for 3 min. After resting, loins were grilled on a 170 °C hot plate grill (Blue Seal Evolution Series EP516 electric griddle; Moffat Limited Christchurch, New Zealand) for 5 min with the fat side down, and then 3 min on the other side to obtain a core temperature of 60 °C (medium degree of doneness). After cooking, loins were rested for 3 min and then trimmed of fat and placed at 40 °C in a Bain Marie to keep warm before serving. The maximum holding time was 50 min. Lamb loin samples were sliced to 0.8 cm thickness (to obtain approximately 20 portions per loin) using a cutting guide and served on demand to consumers with a random 4-digit code. Seven loin samples (one warmup sample and six evaluation samples) were presented monadically to consumers. The warmup sample was presented first and was from the same loin for all 20 consumers within the tasting session. To minimize first-order and carryover effects, the remaining six samples were presented to consumers in order following a Williams Latin square design [19]. The evaluation of the samples was performed using portable divisions for consumer testing in a room with controlled environmental conditions under white light. A total of 8 tasting sessions were carried out with 20 consumers per session. Consumers were given plain water, diluted apple juice and crackers to cleanse their palate between samples. Each sample was rated on four 100 mm nonstructured line scales for overall liking, flavor liking, juiciness and tenderness, anchored at 5 mm with either (0: dislike extremely, not juicy, not tender to 100: like extremely, very juicy, very tender). Consumers also indicated their willingness to pay (NZD per kg) for the following categories of lamb quality: unsatisfactory, good everyday, better than everyday and premium [17].