This study investigated the effect of supplementation with immature Citrus unshiu juice (ICJ) on jelly quality characteristics. According to the amount of ICJ added, the ICJ jelly samples were divided into five groups, to determine differences in physicochemical properties: ICJ-0, ICJ-15, ICJ-30, ICJ-45, and ICJ-60 (immature Citrus unshiu jelly with 0, 15, 30, 45, and 60% ICJ, respectively). Konjac and κ-carrageenan were used as gelling agents, and all groups were gelled, regardless of the ICJ amount. Hunter b (yellowness) value of the jelly was increased with increasing ICJ supplementation, whereas the L (lightness) and a (redness) values were observed to decrease. Moreover, increasing amounts of ICJ resulted in increased levels of total phenolic content and total titratable acidity of the jelly, whereas the pH, moisture, and water activity (Aw) of the jelly were observed to decrease. The water holding capacity showed no significant difference among the groups (P>0.05). Texture properties for hardness and gumminess were significantly higher in the ICJ jellies (treatment group) than in the control (P<0.05). Depending on the ICJ amount, sensory properties of appearance, color, and taste of ICJ jelly were significantly different (P<0.05), but differences in texture and overall acceptability were not significant (P>0.05). Our results confirm that jelly prepared with 45% ICJ supplementation has the highest acceptability. Thus, we conclude that 45% ICJ is the optimal requirement for the preparation of high-quality jelly.

Various jellies were produced depending on the type and concentration of gelling agent (nine types), which added a single or double agent in jelly production. Firstly, jelly was manufactured using nine different single gelling agents and characterized. Secondly, six suitable gelling agents were selected to combine double gelling agents among nine gelling agents. To find the optimum gelling agent condition, jelly was intentionally made around 3.6-3.7 pH and 4- 5 N fracturability. A total of 1.2% gelling agent (both single and double agents) was suitable for making jelly (3.6- 3.7 pH, 4-5 N fracturability). According to the analytical result, the optimum single gelling agent was κ-carrageenan and gellan gum, while a suitable combination of double gelling agents was κ-carrageenan and gellan gum at ratios of 1.0:0.2, 0.8:0.4, and 0.6:0.6 and agar and locust bean gum at ratios of 0.8:0.4, 0.6:0.6.