1. Raw material treatment:
Take eight mature pineapple, the pulp has turned yellow, with pineapple aroma, remove rotten fruit, disease fruit, insect fruit, peel or mechanical method to remove the heart and eye, the pulp has turned yellow, with pineapple aroma, slices, each size thickness of 3-4 mm, fan-shaped.
2. Hardening and color protection measures:
Pineapple pulp belongs to juicy berry type. The purpose of lime soaking is to combine pectin with calcium to form insoluble calcium pectate salt, which can make loose and easy-boiled pulp slightly dense and hard-boiled, and neutralize the acidity contained in the pulp. Lime soaking is to use 3% lime water, that is, add 3 kg of quicklime to 100 kg of water and stir it continuously to dissolve. After a moment of clarification of turbid lime water, take the supernatant and soak pineapple slices for 8 hours, then rinse them with a large amount of water. The pH test paper should be used to test the pH value, and the test paper will not change the blue color to the degree. Raw materials drain water.
3. Treatment of concentrated sugar solution:
The 60% sucrose solution is composed of 60 kilograms of granulated sugar and 40 kilograms of water in 100 kilograms of sugar solution. The pineapple slices were immersed in 60% sugar solution. The sugar solution could be immersed in the raw material just after immersion. The immersion time was 24 hours.
Remove the pineapple slices from the sugar solution, drain the water, and dry them at 65 degrees Celsius for 18 - 20 hours, so that the water content is 16%. The 6P drying and dehumidification machine is equipped with 5.8 m long, 3 m wide, 2.2 m high and 10 cm polyurethane double-sided color steel drying room. It is put into 8 material trucks with 15 layers, 10 kg pineapple slices on each layer, 150 kg on each truck, and 1 200 kg on 8 material trucks. The equipment consumes 7 degrees of electricity per hour and 140 degrees per batch. The drying process is divided into three stages. The first stage is completed with 55 degrees of temperature setting and 2 degrees of time. Hours, continuous heating, continuous operation of the circulating fan, into the second stage, temperature 62 degrees, time 8 hours, humidity set 35%, mode selection of drying + dehumidification, into the third stage, temperature rise to 65 degrees, time set 8 hours, humidity set 20%, mode of drying + dehumidification, the whole process of selection of dry and wet ball sensing signal to control humidity, temperature sensor signal to control temperature.
Dry pineapple slices or pineapple slices will moisture back when they are directly exposed to air, so sealed packaging is needed. If conditions permit, vacuum packaging can be carried out to greatly preserve the color and aroma of pineapple slices or pineapple slices.