I recommend the use of brown sugar, muscovado or coconut sugar. They are healthier than white sugar. However , the look of end product is brownish.
Pectin is expensive and hard to obtain . One tablespoon of calamansi juice might do the trick. Rare ripe fruits are recommended cause of their high pectin content.
1 Liter fruit juice
1 kg sugar
10 ml (1 tbsp) calamansi juice or 1.25g (1/4 tsp) citric acid
400 g fruit, thinly slice (peel in case of orange)
2 tbsp pectin powder (should be mixed with sugar)
1. Select ripe but firm fruits.
2. Wash them thoroughly under running water or through several changes of water.
3. Blanch the fruit by dipping them in hot water. Dipping will help reduce the microbial load and deactivates enzymes that cause browning.
4. For easy peeling, soak fruits in boiling water for one to two minutes. Citrus peeling are soaked overnight before cooking.
5. Cut the fruit thinly and uniformly.
6. Prepare juice as describe in jelly making.
7. Cook the fruits in their own juice or with little water until soft to release the fruit pectin.
8. Supplement the natural acid of the fruit with lemon or calamansi juiced, citric, or tartaric acid as described in jelly making.
9. Boil the juice, fruit slices and sugar, boil rapidly until the setting point is reached according to the methods suggested in jelly- making.
10. Hot-fill the jelly 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.
11. Store them in a cool, dry place from a strong light.
Measure the following physico-chemical properties and and adjust accordingly to set standard. These properties should be uniform every batch. Adjustments can be computed using Pearson’s Square formula.
a. sugar content. Sugar concentration can be increased by adding sugar or lowered by adding water or pulp.
b. pH. This can be lowered by adding citric acid or 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.