1 Liter fruit juice
1 kg sugar, white
10 ml (1 tbsp) calamansi juice or 1.25g (1/4 tsp) citric acid
2 tbsp pectin powder (should be mixed with sugar)
1. Choose fresh fruits rich in pectin and acid. Guava, papaya, banana, citrus, siniguelas, santol and passion fruit can be made into jellies. Select ripe but firm fruits.
2. Prepare and cook the fruits, Wash the fruit thoroughly and remove blossoms, stem ends, and spoiled parts. Blanch the fruit by dipping them in hot water. Drain, cut or crush before measuring. Add water to cover the fruit in the container. Boil the fruit gently until tender. Remove any scum forming on top of the juice.
3. Strain the pulp. Pour the cooked pulp through several layers of muslin cloth, and drain. Do not squeeze pulp if a clear jelly is desired. Fruits rich in pectin can be reoiled for another extraction juice extraction. Either mix the first and second extracts or cook separately.
4. Test for acid. Prepare a standard acid solution by mixing 1 tsp (5 ml) lemon or calamansi juice with 1/2 cup (118 ml) water. Taste and compare the acidity of the unsweetened fruit juice with standard. If the fruit is less acidic than the standard, add a little fruit juice, citric, or tartaric acid.
5. Measure the juice into a cooking pan and boil it after adding sugar. Add sugar before boiling the juice to preserve the color; since the longer the juice and the sugar are heated together, the deeper the color of the resulting jelly. While boiling, do not stir vigorously to avoid trapping air bubbles.
6. Boil the mixture over a strong fire until the jelly point is reached Temperature reaches 105-105oC or sugar concentration reaches 60-65oBrix.Remove the pan from the heat. Remove the scum.
7. Hot-filled the jam into sterile glass jars with lid. The temperature should be 82-85oC. If the filling temperature is too hot, the steam will condense on the inside of the lid and drop down onto the surface of the product. This will dilute the product’s surface making it vulnerable to microbial attack. Set them aside to cool undisturbed for proper gel formation.
8. Store them in a cool, dry place from a strong light.
The following physico-chemical properties can be measured for quality assurance purposes. Properties should be uniform every batch. Adjustments can be computed using Pearson’s Square formula. All artificial preservative can be omitted but will cause decrease in product shelf life.
a. sugar content. Sugar concentration can be increased by adding sugar or can be lowered by adding water or pulp.
b. pH. This can be lowered by adding citric acid or can be increased by adding water or pulp.
c. titrable acidity. Same as in (a), just replace sugar with citric acid. Be cautious because citric acid affects both pH and titrable acidity.