Chilled and frozen retail displa Fig. 11.4 Three types of retail display cabinet for unwrapped products. sliced beef topside after display for bb orative weight loss and appearance of Table 11.1 Relationship between eva vaporative loss(gcm-) Change in appearance 0.0150.025 ing drier, still attractive but darker 0.0250.035 Is darkening, becoming dry and leathery Dry, blackening 0.05-0.10 Black Source: James and Swain. 1986. ration in the appearance of unwrapped meats has been related to the degree of dehydration(Table 11.1), which makes the product unattractive to consumers(James and Swain, 1986). Weight loss on its own cannot only be a measure of performance but also has important economic considera tions to the retailers. In the UK, the direct cost of evaporative weight loss in excessEs pped products in chilled display cabinets was estimated to be 11.2.3 Effects of environmental conditions The rate of dehydration is a function of the temperature, velocity and rel- ative humidity of the air passing over the surface of the food James and Swain(1986) found that changes in relative humidity had a substantial effect with a reduction from 95 to 40% causing increasing weight loss over a 6h display period by a factor of between 14 and 18(Fig. 11.5). The effect of air velocity on weight loss was compounded by that of relativeration in the appearance of unwrapped meats has been related to the degree of dehydration (Table 11.1), which makes the product unattractive to consumers (James and Swain, 1986). Weight loss on its own cannot only be a measure of performance but also has important economic considera￾tions to the retailers. In the UK, the direct cost of evaporative weight loss from unwrapped products in chilled display cabinets was estimated to be in excess of 6.25 m euros per annum (James and Swain, 1986). 11.2.3 Effects of environmental conditions The rate of dehydration is a function of the temperature, velocity and rel￾ative humidity of the air passing over the surface of the food. James and Swain (1986) found that changes in relative humidity had a substantial effect with a reduction from 95 to 40% causing increasing weight loss over a 6 h display period by a factor of between 14 and 18 (Fig. 11.5). The effect of air velocity on weight loss was compounded by that of relative Chilled and frozen retail display 239 Fig. 11.4 Three types of retail display cabinet for unwrapped products. Table 11.1 Relationship between evaporative weight loss and appearance of sliced beef topside after display for 6 h Evaporative loss (g cm-2 ) Change in appearance up to 0.01 Red, attractive and still wet; may lose some brightness 0.015–0.025 Surface becoming drier, still attractive but darker 0.025–0.035 Distinct obvious darkening, becoming dry and leathery 0.05 Dry, blackening 0.05–0.10 Black Source: James and Swain, 1986