Strawberry Jam Processing

The strawberry jam production process uses frozen strawberries or fresh strawberries as raw materials, after strawberry washing, crushing, ingredients blending and boiling to make the strawberry jam products.

The end product strawberry jam should be dark red, have smooth, uniform tissues, and the presence of fruit pieces in the final product, with a pH value range of 3.0 to 3.5, and solid brix is 60-65Brix.

The strawberry jam processing machines involve strawberry washing machines(Only for the fresh strawberry as raw material), strawberry milling machines, colloid mills for dissolving powder and pectin materials, strawberry jam blending and cooking tanks, strawberry jam filling machines, RO water treatment system and CIP system.

The main ingredients used for strawberry jam processing are frozen strawberry, water, sugar, fructose syrup, honey, acid, modified starch, strawberry flavor, color agent, and preservatives.

The capacity for strawberry jam processing is from 300kg/h-3,000 kg/h, and the production equipment can be in continuous or batch based on customers’ requirements and capacity.

The end products of the strawberry jam can be filled into glass jars, soft bags, cans, or other consumable containers, and can have a shelf life of around 1 to 2 years when stored unopened in a cool, dark place.

Strawberry jam processing should choose the fully ripened, red color, stems removed, and cleaned frozen strawberries. Some manufacturers also use freshly ripened strawberries as raw materials, if fresh strawberries, they should be thoroughly cleaned by a bubble washing machine and brush washing machines to remove the dirty parts of the strawberry.

Fresh strawberry stems will be removed manually, and then fed into the air bubble washing machines to clean the dirty matter and pesticide residue on the fruit surface through water and cleaning solutions. After that, the strawberries will be lifted to the belt conveyor to sort out the low-quality and rotten fruits.

Frozen strawberries after natural thawing or machine thawing will be fed into tooth crushers. The sieve screen of the crusher is set to be 3mm-5mm, so that the strawberry can be crushed evenly and with small strawberry pulp. If no pieces or fruit chunks are desired in the end products, the strawberries after crushing and milling need to be pumped into the pulping machines with the sieve screen 1.2mm.

The sugar, modified starch and pectin need to be dissolved in a colloid mill or water powder mixer. When dissolving, the sugar and water feed ratio is about 1:5; The modified starch and water ratio is 1:6; The pectin and water ratio is 1:10. When dissolving these powder products with the colloid mill, need to feed cooling water all the time to avoid overheating of the machine and the colloid mill is blocked.

Strawberry jam preparation and boiling is the core process in the strawberry jam processing plant, the whole process is conducted in the vacuum blending and boiling tanks, and the vacuum tanks can be equipped with 2 sets to realize the continuous production. The boiling tank has the following features:

SUS304, jacketed tank with coil jacket and rock wool insulation, atmospheric pressure tank, negative pressure resistance -0.078Mpa, upper and lower oval heads, CIP cleaning ball, pressure-tight manhole, respirator with manual butterfly valve, central coaxial double Stirring, central paddle + wall scraping 60rpm (scraping the wall should be staggered up and down, the wall can be scraped), mechanical seal, frequency conversion gear motor, mirror light, steam heating, top feeding Port, water inlet, drain port, tank top sight glass. The temperature sensor interface at the bottom of the tank, the capacitance low liquid level gauge interface, and the pressure gauge on the top.

There are 3 processes when preparing the fruit jam:

Firstly, feed the crushed strawberry pulp, sugar, potassium sorbate, acid, and water into the vacuum boiling tank, then start the agitator for mixing and increase the temperature to 80-85℃hold for 20 minutes.

Secondly, dissolving pectin and xanthan gum in water and then pumped into the vacuum boiling tanks, mixing and increasing the temperature to 80-85℃hold for 20 minutes.

Thirdly, dissolving modified starch and color agent, then feed into boiling tanks, mixing and increasing temperature to 80-85℃hold for 15 minutes until the end product Brix value reaches 60-65Brix.

The strawberry jam will be filled into soft bags, jars, or cans. As the feature of high viscosity, the strawberry jam will be pumped into the piston fillers by the double screw pumps, and the filling will use hot filling so that when filling, this temperature can also have an effect on killing bacteria in the jam. Some manufacturers will also put the containers in water bath pasteurizers or spray tunnel pasteurizers to do the secondary pasteurizing then cool the containers to room temperature and pack and store in the warehouse.