## 3 Results and Discussion
#### 3.1.1 Techno-Functional Characteristics  
The absorption characteristics of \(L\). _cylindrica_ seed press cake powder and blends are shown in Table 1.  
The water holding capacity (WHC) values ranged from 1.76 \(\pm\) 0.12 to 3.62 \(\pm\) 0.44 g H\({}_{2}\)O/g d.b., with pure \(L\). _cylindrica_ powder (LP 100%) exhibiting the highest value at 3.62 \(\pm\) 0.44 g H\({}_{2}\)O/g d.b., while pure tapioca flour (TF 100%) showed the lowest at 1.76 \(\pm\) 0.12 g H\({}_{2}\)O/g d.b. The blends demonstrated intermediate values, showing a clear decreasing trend with increases in luffa powder content. Water absorption capacity (WAC) exhibited values between 1.79 \(\pm\) 0.03 and 2.88 \(\pm\) 0.02 g H\({}_{2}\)O/g d.b., with LP 100% the highest WAC at 2.88 \(\pm\) 0.02 g H\({}_{2}\)O/g d.b., while TF 100% showed the lowest value at 1.79 \(\pm\) 0.03 g H\({}_{2}\)O/g d.b. The blends showed a progressive decrease in WAC with increasing tapioca content. These results, showing that Luffa powder (LP) exhibits the highest WHC and WAC, can be attributed to its fibrous and highly porous structure, which provides a large surface area and abundant hydrophilic sites for water interaction and absorption. This finding aligns with studies on other high-fiber plant residues, where the presence of hydroxyl groups and open matrix architecture significantly enhances water retention capacity [25]. Similar water absorption behavior has been reported for various dietary fiber sources, such as okra peel, rice bran, and spent coffee grounds, all of which demonstrate strong WAC due to their microstructural features [26; 27]. In the present study, _Luffa cylindrica_ powder contained 59.72 g/100 g of insoluble dietary fiber (IDF) and 3.89 g/100 g of soluble dietary fiber (SDF), while the meat substitute formulation contained 16.29 g/100 g IDF and 2.92 g/100 g SDF. These values support the observed water absorption capacity of both materials. However, the simultaneous decrease in WHC and increase in WAC with increasing LP concentrations can be explained by the distinction between water absorption and water retention. While LP is highly efficient at absorbing water into its structure, it lacks the ability to retain that water under external forces such as centrifugation or mechanical stress. WHC reflects not only water uptake, but also the strength and integrity of the surrounding matrix in holding the water in place. As the proportion of LP increases and that of tapioca flour (TF) decreases, the composite matrix becomes more fragmented and fibrous, reducing its cohesiveness and structural integrity. Tapioca starch, in contrast, is well known for its gel-forming ability, contributing to a continuous and stable gel network that effectively traps and retains water [28]. When the TF content is lowered, this gel matrix is weakened or disrupted and the LP-dominated structure does not compensate sufficiently. As a result, even though more water is absorbed due to LP's porosity (high WAC), less water is physically held within the matrix, leading to a lower WHC. These findings underscore the critical role of matrix cohesion and polymer interactions in determining the functional hydration properties of plant-based formulations. The oil absorption capacity (OAC) remained relatively consistent across samples, ranging from 1.69 \(\pm\) 0.02 to 2.08 \(\pm\) 0.06 g oil/ g d.b. Pure tapioca flour exhibited the highest OAC at 2.08 \(\pm\) 0.06 g oil/g d.b., while pure _L. cylindrica_ powder showed the lowest at 1.69 \(\pm\) 0.02 g oil/g d.b. This trend suggests that TF's starchy matrix, particularly upon gelatinization, may provide more nonpolar binding sites or physical spaces for oil entrapment. In contrast, although LP is fibrous and porous, its higher polarity and hydrophilicity limit its oil affinity. This is consistent with earlier reports, where protein-rich or starch-rich matrices showed higher OAC than fiber-dominant materials [29]. Additionally, the increased surface polarity of LP may hinder effective oil retention.