Optimasi Teknik Proses Ekstrusi Pet Food Dengan Respond Surface Methodology Terhadap Kualitas Fisikokimia Dan Akseptabilitas Produk

Abstract

Industri pet food berkembang pesat seiring meningkatnya kepemilikan kucing, tetapi produksi domestik masih tertinggal sehingga ketergantungan pada produk impor dan risiko gangguan rantai pasok tetap tinggi. Proses ekstrusi menjadi teknologi utama produksi dry pet food karena fleksibilitas formulasi dan keamanan produk, namun kualitas fisikokimia kibble sangat ditentukan oleh pengaturan kadar air dan feed rate. Penelitian ini bertujuan mengoptimalkan kedua parameter tersebut menggunakan pendekatan response surface methodology (RSM) serta mengkaji implikasinya terhadap akseptabilitas dan respons pencernaan kucing domestik. Penelitian dilaksanakan dalam dua tahap. Tahap I merupakan optimasi proses ekstrusi menggunakan rancangan central composite design dengan dua faktor, yaitu kadar air 16,55%–26,45% dan feed rate 13,96–21,04 kg jam-1. Respons yang diamati meliputi expansion ratio (ER), true density (TD), water absorption index (WAI), water soluble index (WSI), dan protein kasar (PK). Data dimodelkan dengan persamaan kuadratik dan dievaluasi melalui ANOVA, kelayakan prediksi, dan optimasi numerik. Tahap II adalah uji akseptabilitas menggunakan delapan belas kucing domestik yang dibagi ke dalam dua kelompok; satu menerima kibble hasil ekstrusi optimum dan satu lagi menerima diet komersial pembanding. Parameter yang diamati mencakup waktu penciuman, lama makan, konsumsi, sisa pakan, frekuensi defekasi, dan skor feses. Model kuadratik memberikan kecocokan yang sangat baik untuk ER, TD, WAI, dan WSI dengan nilai koefisien determinasi (R²) berturut-turut sekitar 0,76; 0,94; 0,95; dan 0,99, sedangkan PK relatif stabil terhadap perubahan kondisi proses. Optimasi menghasilkan kombinasi kadar air 22,245% dan feed rate 17,357 kg jam-1 dengan desirability 0,918. Pada kondisi ini diperoleh ER 1,666, TD 1,151 g cm-³, WAI 4,863 g gel g-1, WSI 10,804%, dan PK 38,967%, dengan hasil uji konfirmasi berada dalam selang prediksi 95%. Uji akseptabilitas menunjukkan bahwa kucing mengonsumsi kibble ekstrusi lebih banyak (79,78 g hari-1) dengan sisa pakan lebih rendah (20,22 g) dibandingkan diet komersial (68,01 g hari-1; 31,99 g), serta memiliki skor feses yang lebih baik (3,33 vs 3,90) tanpa perbedaan berarti pada frekuensi defekasi dan waktu penciuman. Hal tersebut menjelaskan bahwa pengaturan kadar air dan feed rate yang tepat mampu menghasilkan kibble dengan kualitas fisikokimia optimum yang meningkatkan palatabilitas dan mendukung kualitas pencernaan kucing.

The pet food industry has expanded rapidly in line with the rising trend of cat ownership; however, domestic production capacity has not kept pace, resulting in continued dependence on imported products and heightened vulnerability to supply chain disruptions. Extrusion has become the primary technology for manufacturing dry pet food due to its formulation flexibility and product safety, yet the physicochemical quality of kibble is highly dependent on the precise control of moisture content and feed rate. This study aimed to optimize these two parameters using response surface methodology (RSM) and to evaluate their implications for the acceptability and digestive response of domestic cats. The research was conducted in two stages. Stage I focused on optimizing the extrusion process using a central composite design with two factors: moisture content ranging from 16.55% to 26.45% and feed rate from 13.96 to 21.04 kg h-1. The measured responses included expansion ratio (ER), true density (TD), water absorption index (WAI), water-soluble index (WSI), and crude protein (CP). Quadratic models were fitted to the data and evaluated through analysis of variance, prediction adequacy, and numerical optimization. Stage II involved an acceptability trial using eighteen domestic cats allocated into two groups: one receiving the optimized extruded kibble and the other receiving a commercial control diet. Observed parameters included sniffing time, eating duration, intake, leftover feed, defecation frequency, and fecal score. The quadratic models showed excellent fit for ER, TD, WAI, and WSI, with coefficients of determination (R²) of approximately 0.76, 0.94, 0.95, and 0.99, respectively, while CP remained relatively stable across processing conditions. Optimization identified an optimal combination of 22.245% moisture content and a 17.357 kg h-1 feed rate, achieving a desirability score of 0.918. Under these conditions, the predicted responses were ER 1.666, TD 1.151 g cm-³, WAI 4.863 g gel g-1, WSI 10.804%, and CP 38.967%, all of which were confirmed experimentally within the 95% prediction interval. The acceptability test demonstrated that cats consumed more of the optimized extruded kibble (79.78 g day-1) and left less uneaten feed (20.22 g) compared with the commercial diet (68.01 g day-1; 31.99 g). Additionally, cats fed the optimized kibble exhibited better fecal scores (3.33 versus 3.90), with no significant differences in sniffing time or defecation frequency. These findings indicate that precise adjustment of moisture content and feed rate can produce kibble with optimal physicochemical characteristics that simultaneously enhance palatability and support improved digestive quality in cats.