Emulsion processing attributes can be well determined through WHC and ES and both are interlinked. Higher ES is directly linked with higher WHC (Jairath et al. 2016). Further, a significant impact of particle size on WHC was might be due association of protein extraction with particle size. Since extraction of myosin is very important to make a stable emulsion, the lower particle size played a probable role in in more swelling of myofibrillar proteins, consequently leading to more water retention and stable emulsion (Santhi et al. 2015). Lower WHC at higher fat level indicated the unavailability of protein or water that might link or cover the fat globules during emulsion making resulting in lower emulsion stability (Hoogenkamp 2011). Furthermore, with increase in fat content, the WHC and ES decreases as suggested by Toledo and Totosaus (2020). Similar observations were made and it was mentioned that texture modification in low-fat ground buffalo meat patties resulted in increased water binding by hydrocolloids (Suman and Sharma 2003). Lower emulsion processing attributes with longer tumbling time suggested its negative impact on waterbinding properties and stability.
Higher cooking yield in products prepared from 3mm particle size, 10% fat level and 1 hour tumbling depicted the role of ES and WHC in reducing the cooking losses. Cooking yield is governed by multiple factors depending on the water holding properties, emulsion stability, shrinkage etc., hence the present findings correlate with the enhanced binding ability with smaller particle, lower fat and optimum tumbling time for binding protein extraction. However, in contrary, Berry et al. (1999) found that neither methods of size reduction nor size of opening used in instrument affected the cook yield of restructured steakettes. However, Suman and Sharma (2003) found significantly (P ≤ 0.05) higher cooking yields for ground buffalo meat patties at different low-fat levels. The change in height was evaluated to judge the shrinkage of the meat rolls formed in a round mold after cooking. Suman and Sharma (2003) also showed a significant (P ≤ 0.05) difference in the patties for parameters like gain in height; it was significantly higher (P ≤ 0.05) for low-fat ground buffalo meat patties, which could be attributed to the gelling action of binders. The change in diameter was evaluated to assess the shrinkage of the cooked meat rolls before making the slices. The results observed are again having the trend similar to the parameters like change in height where more particle size, more fat and more tumbling was associated with more change in dimensions and lesser stability features like emulsion stability. However other researchers have reported no significant differences in diameter change of restructured beef steaks (Chen and Trout 1991; Esguerra 1994) but saw significant (P ≤ 0.05) differences in thickness changes (Chen and Trout 1991; Esguerra 1994). Berry et al. (1987) reported that restructured steak distortion was more extensive in steaks manufactured with large and small meat flakes compared to steaks processed from intermediate size meat flakes. Similarly, Suman and Sharma (2003) noticed no significant difference on dimensional changes of patties prepared with 3, 4 or 6 mm grind size. Further, the slice-ability was evaluated to know the ease with which the slices could be prepared from meat rolls formed after cooking in a round mold and the processing attributes like WHC and ES were associated with the ease of slicing. Moreover, the fold test validated the positive impact of lower particle size on the binding ability, leading to higher scores while fold test.
The pH of the products did not get affected with any kind of treatment and results corroborates with Boles and Shand, (1998) who found that binders and particle size reduction did not affect the pH of beef steakettes. Similarly, Suman and Sharma (2003) documented no effect of grind size on the pH of cooked patties. No significant effect of size, fat level and tumbling on TBARS value depicted the suitability of the processing protocol. However, the higher values in product with 20% fat level could have been due to higher fat and higher oxidative effect in the product.
As moisture and fat content in a cooked meat are inversely related with each other (Yim et al. 2016), the moisture content was higher in the products prepared from low fat level. Further particle size also affected the moisture and was significantly higher in the products prepared from smaller particle size. However, no effect of particle size on moisture content was observed by Sen and Karim (2003). Lower moisture content in products prepared from emulsion that underwent tumbling for longer duration was might be attributable to dehydration effect on the meat batter in prolonged tumbling time.
The results of protein content analysis revealed that particle size and tumbling time variation had no significant effect on the protein content of product however the fat content variation indicated some effect on the proportional protein content where the products containing 10 per cent fat had significantly (P ≤ 0.05) higher protein content than the product variant containing 15 and 20 percent fat. Similar findings were there for moisture and protein contents which were significantly (P ≤ 0.05) higher for low-fat ground buffalo meat patties compared to controls (Suman and Sharma 2003). The ash content of the product did not reveal any significant change with the particle size, fat content and tumbling time variation. The findings were corroborated with the results of Boles and Shand (1998) that exhibited no impact of size reduction on the proximate composition of restructured beef steakettes.
The hardness in all the products was at par irrespective of any variation in size, fat level and tumbling time. However, Roth et al. (1999) found direct association of particle size with the in reduced-fat ground beef patties. Increase in springiness and cohesiveness values in products developed from 3mm particle size, 10 percent fat and 1 hour tumbling time product had significantly (P ≤ 0.05) lower values in comparison to 3 hour tumbled product. The hardness and springiness indicated that 3 mm particle product with 10 percent fat and 1 hour tumbling time was having appreciable features than the other variants under the study. Similar findings were reported by Young et al. (1991) where they observed that among the various formulations of ground chicken meat patties containing 5, 10, 15 and 20% fat, lower fat patties were harder and springier than those containing higher fat levels. Cohesiveness parameter showed that products prepared with 3 mm particle were having higher values in comparison to other two variants of particle size. Similarly, Trout et al. (1992b) reported higher springiness and cohesiveness for low-fat ground beef patties, among combinations with 5, 10, 15, 20, 25 and 30% fat.
The gumminess and chewiness values found higher in products prepared with 3 mm particle size that was probably due to greater softness, faster sample breakdown in chewing and a greater number of smaller sizes chewed pieces imparted by small size particles in contrast to the larger grind size (Berry et al. 1999). Higher firmness and toughness in products containing lower level of fat content (10%) was also found by Lin and Keeton (1994) in also low-fat ground beef patties prepared using flaking, grinding as well as a combination of flaking and grinding, where shear force values were maximum for ground patties and minimum for flaked ones. Toughness parameter revealed that although higher values were there for 6 mm particle in comparison to other two variants with respect to particle size but the difference was non significant. Similarly, higher shear force values in low-fat ground buffalo meat patties were observed by Suman and Sharma (2003).
The colour profile of all variants was more or less at par. However, the fat variation and tumbling time in the product resulted in the significantly (P ≤ 0.05)higher values for L* in the products prepared from 10 per cent fat and 1 hour tumbling time in comparison to the other respective variants. Das and Rajkumar (2013) also reported increase in redness in the patties prepared with low fat content, however, on contrary lightness was lowered in the low-fat products. The results were on the same lines with those documented by Trout et al. (1992b) in ground beef.