METHODS: The parameters of spray-dried 'cempedak' fruit powder under study include inlet air temperature (140-180°C) and maltodextrin (DE 10) concentrations (5-15% w/w). Response surface methodology involving 14 runs was used to assess the effects of inlet temperature and maltodextrin on the powder flow properties and reconstitution properties of the spray-dried 'cempedak' powder.
RESULTS: Out of the tested responses, only bulk density, change in cake height ratio, and water solubility index had a high coefficient of determination value. Inlet air temperature was found to be the main parameter to affect the bulk density, caking and water solubility index, when compared to maltodextrin concentration. By setting minimization of caking and maximization of water solubility index as the main determinants, the optimal parameters of 160°C inlet temperature and 15% (w/w) maltodextrin DE10 were generated, with a desirability of 0.697.
CONCLUSIONS: The powder produced under optimal conditions (160°C and 15% w/w maltodextrin) had a low bulk density (480.01 kg/m3), low caking properties (0.17 change in cake height ratio), and a high solubility index (88.69). This indicates that the powder is stable to be stored (without caking) and will have good reconstitution when added to water.
METHODS: The innovative sous vide treatments were cooked at 45°C and 65°C for 6 h (SV45-65), common sous vide treatment at 45°C and 65°C for 3 h (SV45 and SV65) and traditional cooking at 75°C for 30 min (CON75). Water loss and cooking loss, as well as the physical properties (color and shear force) and chemical properties (protein and collagen solubility) of the treated meat, were investigated.
RESULTS: The results obtained indicated that the innovative sous vide with double thermal treatment (SV45-65) and cooked with air presence (CON75) resulted to lower a* and higher b* values, respectively. The water loss and cooking loss increased when temperature increased from 45°C to 65°C, and lower water loss was recorded in SV45 and CON75. These samples presented higher water content and revealed strong correlation to protein solubility. Warner-Bratzler shear force (SF) analysis showed the marked interaction between cooking temperature and time. Sample cooked at a high temperature (CON75) and a long period (SV45-65) showed a significantly lower value of SF than sample SV65 (p<0.05). Interestingly, there was no difference in SF values between SV45-65 and CON75.
CONCLUSION: The innovative sous vide treatment with double thermal effect appears an attractive cooking method as compared to common sous vide and traditional cooking method, as it has a potential for improving tenderness values of cooked beef semitendinosus muscle.