Agar was first reported as a suspending agent for suspended fruit drinks.
Ying Zhou first introduced the use of agar for the production of citrus fruit suspension drinks. Fang Xiugui and others experimented the effect of pectin, gelatin, agar, ginkgo gum, sodium alginate, carboxymethyl cellulose (CMC) and other colloids on the suspension of citrus juice cells, and concluded that agar is the most suitable suspending agent, the use of concentration of 0.18% to 0.20%, in the presence of appropriate concentration of ginkgo gum, the suspension effect is better.
Li Zhengming also studied the use of agar for suspended citrus juice cells and concluded that the combination of agar plus citrate could achieve satisfactory results.
The best results of agar for citrus juice cell suspension experiments were: 0.25% agar dosage, pH 3.6-4.0 of the beverage, and not too long heating time after mixing.
Zhu Makuhan concluded that agar is the strongest gelling agent among the thickeners used in current production, and the gelling effect was evident even at 0.04% concentration, and the beverage had good transparency and smooth taste.
Hu Guohua used agar in basil seed suspension drinks and pointed out that the main factors affecting agar suspension are concentration, temperature, pH and electrolytes. High temperature and prolonged duration of high temperature and strong acidity of the solution can cause agar degradation and failure.
The gel strength and viscosity of agar are low in solutions with low pH and increase with increasing pH, with maximum viscosity at pH 6-11. The gel strength and viscosity of agar solution decreased with the increase of high-temperature duration, and after the high-temperature duration exceeded 5h, the solution viscosity was very small and could not form gelling.
Therefore, the strict control of process temperature and high-temperature duration, and the selection of suitable acidifiers and pH are the keys to the success or failure of agar suspension.
At the same time, the addition of CMC also has a great influence on the gel strength and fluidity of agar. The beverage with Agar-CMC as the main suspending agent has relatively good fluidity and stability, is transparent, and not easy to precipitate gel, showing a good combination of synergistic properties. Numerous studies have also demonstrated that Agar-CMC is an excellent suspending agent combination, resulting in clear and transparent products with good stability.
Dong Mingming et al. used agar in combination with Dianthus polysaccharide gum to produce a satisfactory aloe vera suspension drink with a suspension formulation of 0.05% agar, 0.03% Dianthus polysaccharide gum, and 0.03% potassium chloride.
Wang Yanzhe et al. used a suspension formulation of agar 0.20%, CMC 0.20%, and gelatin 0.10% to achieve good suspension stabilization of a beverage containing 7% chrysanthemum petals.