Instrumental measurements of juiciness of meat and plant-based burgers

Plant-based burgers (PBB) are food products that are designed to have meat-like characteristics, but do not contain any animal-derived ingredients. The sensorial experience of PBB complains about their lack of juiciness of cooked products compared to the meat-based burgers (MBB). As many analytical techniques, established for meat juiciness evaluation, would not seem to be sufficient to characterize PBB the objective of this study is to quantify PBB’s juiciness by novel techniques in the burger from the original frozen/fresh status to what the consumer could perceives in his/her mouth. The study was performed on 1 MBB, 1 commercial PBB and 6 self-made prototypes of PBB, for a total of 80 burgers analyzed both raw and cooked. The traditional methods employed to quantify meat instrumental juiciness were modified to make them suitable for PBB juiciness evaluation. Physical analyses were performed by two new measuring instruments: Meat Cooking Shrinkage and Water Holding Capacity Trend instruments. These semi-automatic instruments, which measure different parameters on the same sample, provide accurate and fast measurements. Data were analysed by ANOVA GLM procedure (Tukey test, P<0.05). The results were expressed as percentage on the wet basis to provide a correct comparison of the obtained values. The following parameters were evaluated: total moisture content (TMC), meat cooking shrinkage (MCS), fluid to the mouth (FTM) and cooked specific fluid content per volume (CSFC). The meat-based burger had a TMC equal to 71%, a significantly higher value (+9.6%) than that from the PBB average. Both MBB and PBB had similar FTM average (48%), but MCS was significantly higher (+11%) in MBB (24%) compared to PBB average. It can be concluded that MBB retained more water than PBB with a CSFC of 0.84 mg/mm3, a value significantly higher (+0.222 mg/mm3) than that from PBB average. All the means were significantly different at P<0.05 level. Plant-based burger showed a lower water retention than MBB because plant-based proteins cannot bind together to simulate the interstitial spaces between meat muscle myofilaments. These myofilaments trap and retain water, which is released during chewing to create the juicy sensation. Further innovations must be explored to reproduce the type of capillary systems of muscle that are crucial to the juiciness of cooked PBB.