Optimization of Processing Conditions for Sea Grape (Caulerpa racemosa) Sauce Using Response Surface Methodology

Caulerpa racemosa, a green seaweed traditionally consumed fresh in coastal Indonesia, holds untapped potential as a functional food ingredient due to its rich content of bioactive compounds. However, its high moisture content and enzymatic activity limit shelf life, hindering commercialization. This study aimed to develop a functional seaweed-based sauce by optimizing the processing conditions using Response Surface Methodology (RSM). A Box-Behnken design was employed to investigate the impact of cornstarch concentration (2–4%), cooking temperature (70–100℃), and cooking time (30–60 minutes) on the sauce's physical properties, specifically pH and Total Dissolved Solids (TDS). Statistical analysis identified a significant quadratic model for TDS (R^² = 0.76, p < 0.05) and a linear model for pH (p < 0.0001), with starch concentration having the most dominant effect. The optimal formulation, consisting of 2.99% cornstarch, 86.35℃, and 44.11 minutes, yielded a sauce with a pH of 3.435 and a TDS of 23.2%, as confirmed through experimental verification with minimal deviation. The acidic pH ensures microbiological safety, while high TDS reflects superior viscosity and nutrient retention. Organoleptic testing also indicated favorable acceptance for appearance, aroma, and taste, especially in formulations near the optimal condition. This approach enables efficient extraction of seaweed bioactives and effective gelatinization of starch, resulting in a stable, shelf-ready product. The study demonstrates a novel application of C. racemosa in processed foods, offering a sustainable solution to valorize local marine resources and expand the market for functional foods.