Development and Utilization Value and Methods of Kernel Apricot Flesh

I. Dried Apricot Processing

1. Process flow: apricot flesh → washing → sulfur fumigation → drying → finished product

2. Technical points:

(1) Washing. Select flesh that is uniform in appearance, fully ripe, with no fuzz on the fruit surface, small in fruit size and thick in flesh; wash clean with water and drain off the moisture.

(2) Sulfur fumigation. Send the material baskets or bamboo trays holding the apricot slices onto the wooden racks in the fumigation room, pour the burning charcoal into the iron pan in the center of the fumigation room, quickly sprinkle sulfur (3-4 kg of sulfur per 1000 kg of apricot slices) onto the charcoal, then leave the fumigation room immediately, then tightly seal the doors and windows, fumigate for about 2 hours, and when the fruit slices become yellow and semi-transparent (when water droplets the size of mung beans appear in the apricot bowl), open the doors and windows for ventilation. After the air has fully exchanged, move the apricot slices outdoors to air for 1-2 hours, then carry out drying.

(3) Drying: Send the sulfur-fumigated apricot slices into the baking room, arrange them layer by layer on the wooden racks, then close the doors and windows, light the fire and supply heat for drying. During the first 4-6 hours, keep the room temperature at 45-50°C, then gradually raise it to 70-80°C. As the moisture in the apricot slices evaporates and the indoor humidity increases, the doors, windows and ventilation holes should be opened in good time to discharge the water vapor, and the closing time should be controlled according to the indoor dryness and humidity and the degree of drying of the apricot slices. During the drying process, the apricot slices on the upper and lower layers of the baking racks should be swapped so that they are heated evenly, striving to dry the same batch of raw material at the same time. After 12-24 hours, the moisture content of the apricot slices should preferably be 20-24%. If the drying temperature and humidity are not properly controlled, the drying time will be prolonged, resulting in poor color and inferior quality of the product.

(4) Finished product: Soften the prepared dried apricots, then pick out fragments and foreign matter, carry out grading, and pack by grade in wooden boxes or cardboard boxes. Before boxing, the boxes must be lined with packaging film or packaging paper to prevent the dried apricots from absorbing moisture. After being put into boxes, the dried apricots should be stored in an environment with a temperature of 0-5°C and a relative humidity of about 65%, and should be avoided in places exposed to direct sunlight.

3. Characteristics of the finished product: The quality requirements for the finished dried apricots are orange-yellow, soft, not sticky to the hand, semi-transparent, uniform in size and neat in shape, with a rich sweet-and-sour flavor, and a moisture content of no more than 18%.

II. Preserved Apricot Processing

1. Process flow: apricot flesh → washing → sulfur fumigation → sugar boiling → drying → shaping and packaging → finished product

2. Technical points: (1) Washing and sulfur fumigation. Select flesh with no dry scars, no rot, uniform in appearance and at the eight-tenths ripe stage, wash clean and drain off the moisture, then place the apricot bowls upward in bamboo trays and move them into the sulfur fumigation room for sulfur fumigation. Use 0.9 kg of sulfur per 100 kg of flesh, fumigate for 3-5 hours, until water droplets appear in the apricot bowls and the flesh turns pale yellow, or soak in a 1-3 g/kg sodium bisulfite solution for 1-2 hours.

(2) Sugar boiling and drying. When the flesh is soft and has a relatively high moisture content, the multiple-boiling method can be used. For the first boiling, bring a sugar solution with a mass fraction of 30% to a boil, then pour in the flesh and boil for 10 minutes, during which it should be gently stirred constantly so that it is heated evenly, then pour the flesh together with the sugar solution into a vat and soak for 1 day. For the second boiling, adjust the mass fraction of the sugar solution to 50% (the sugar solution from the first boiling can be used), boil the flesh for 15-20 minutes, then pour the flesh together with the sugar solution into a vat and soak for 1 day, then take out the flesh and drain off the sugar solution, place it with the apricot bowls facing upward on bamboo trays and send it into the baking room, keep the temperature at 50-60°C, and bake for 24-36 hours, until it is no longer sticky to the hand.

(3) Shaping and packaging. After the flesh has cooled, flatten and shape it, keeping the flesh in its original shape as far as possible, then carry out grading and packaging. Generally, moisture-proof wax paper or food-grade plastic bags are used for packaging, sealed in good time, then put into cardboard boxes and placed in a ventilated and dry place.

3. Characteristics of the finished product: The preserved apricots are golden yellow or red-yellow, neat in shape, semi-transparent and suitably sweet-and-sour, with a moisture content of about 18%, a total sugar content of 68-72%, and a sulfur content of no more than 0.2%.

III. Apricot Juice Processing

1. Process flow: material selection → washing → crushing → pre-cooking → pressing → coarse filtration → clarification → fine filtration → homogenization → deoxygenation → sugar and acidity adjustment → canning → sterilization → finished product

2. Technical points: (1) Material selection and washing. Select flesh with good flavor, slightly higher acidity, easy juice extraction, high juice yield, orange-yellow color, free of insects and free of damage, and fully ripe; wash clean with water.

(2) Crushing and pre-cooking. It is best to cut the apricot flesh into small pieces 0.5-1 cm long (do not cut too finely). Pre-cook equal amounts of the crushed flesh and water in a stainless steel pot for 15-30 minutes, with the temperature controlled at 60-70°C, so that the flesh is fully softened, and at the same time add a little vitamin C, citric acid or a small amount of table salt to help protect the color.

(3) Pressing and coarse filtration. The apricot flesh that has undergone crushing and pre-cooking should be pressed immediately with a press. Add a small amount of water to the pomace after the first pressing, soak for several hours and then press again. Filter off the suspended matter and impurities from the squeezed apricot juice with a filter screen or filter bag.

(4) Clarification and fine filtration. Coarse filtration only removes large particles of impurities and suspended matter; clarification and fine filtration mainly remove the colloids in the apricot juice, making the apricot juice clear and transparent.

(5) Homogenization and deoxygenation. Cloudy apricot juice must be homogenized; the apricot juice passes under high pressure through homogenization pores of 0.002-0.003 mm, making the particles in the juice finer and more uniform. The oxygen in the apricot juice can be removed by the antioxidant method, that is, adding a small amount of antioxidants such as vitamin C when canning the apricot juice.

(6) Adjustment of sugar degree and acidity. Only when the ratio of sugar content to acid content in the apricot juice is appropriate is the flavor good; generally the sugar-to-acid ratio is 13:1-15:1, and the sugar content is about 17%. The adjustment method is to use filtered concentrated sugar solution to adjust the sugar content, and use a citric acid solution with a mass fraction of 0.1% to adjust its acidity.

(7) Canning and sterilization. Heat the apricot juice to 80-90°C, fill into cans while hot, and seal immediately. Sterilize with high-temperature boiling water; after being put into the pot, the water temperature rises to 100°C within 3-5 minutes and is maintained for about 10 minutes. After sterilization, soft packaging can be placed in cold water to cool rapidly; beverages in glass bottles can be cooled by a staged cooling method, wipe off the water droplets, and the finished product is obtained.

3. Characteristics of the finished product: The processed apricot juice is dark yellow or orange-yellow in color, with a soluble solids content of 15-20% and an acid content of 0.5-1%, and has a rich apricot flavor.

IV. Apricot Jam Processing

1. Process flow: material selection → washing → pre-cooking and softening → pulping → sugar and acidity adjustment and concentration → bottling → sealing → sterilization → cooling → finished product

2. Technical points: (1) Material selection and washing. Same as the processing of apricot juice. (2) Pre-cooking and softening. Add the flesh and an appropriate amount of water to a jacketed pot, with clean water at 10-20% of the mass of the flesh being suitable, and soften for 10-20 minutes to facilitate pulping. (3) Pulping. Use a pulping machine with a pore diameter of 0.7-1 mm to pulp the softened flesh 1-2 times. (4) Sugar and acidity adjustment and concentration. Pour the fruit puree and white granulated sugar into a double-layer pot at a ratio of 1:0.8-1:1, heat and concentrate, stirring constantly, until the soluble solids content reaches more than 60%, then stop concentrating. (5) Bottling and sealing. Generally, four-twist bottles are used as containers; the temperature should be kept above 85°C during bottling, and the bottle mouth must not be contaminated with jam. Seal immediately after bottling, and the jam temperature must not be lower than 80°C when sealing. (6) Sterilization and cooling. Use boiling water sterilization; the sterilization formula is 5-20 minutes/100°C. Cool in stages after sterilization.

3. Characteristics of the finished product: The jam body is yellow or light yellow, glossy, viscous and gelatinous, flowing slowly, with no sugar crystals precipitated and no impurities, with the unique flavor of apricot jam and no off-flavor. The total sugar content is not less than 55%, and the soluble solids content is greater than 60%.

V. Apricot Wine Brewing

1. Process flow: material selection → washing → crushing → component adjustment → primary fermentation → separation → secondary fermentation → aging → fining → freezing → filtration → storage → filtration → sterilization → filling → sealing → finished product

2. Technical points: (1) Material selection and washing. Same as the processing of apricot juice. (2) Crushing. Use a roller crusher for crushing; it is required only that the flesh be squeezed and broken. (3) Primary fermentation. Put the crushed fruit into a fermentation tank, add white sugar water with a mass fraction of 10% to adjust the sugar degree to a mass fraction of 20-24%. Then add 100 mg/kg of potassium metabisulfite and a small amount of pectinase, then add 3-5% fruit wine yeast culture liquid, and after mixing evenly, primary fermentation can proceed. The fermentation temperature is controlled at 20-25°C, the fermentation time is 5-7 days; when the sugar content of the fermentation liquid drops to 1-2%, the juice begins to clear and the skins and pomace sink, and the primary fermentation ends. (4) Secondary fermentation. After the primary fermentation ends, separation is carried out; the separated fruit juice is pumped into the secondary fermentation tank, the pomace is press-filtered, the clear liquid is mixed into the secondary fermentation tank, and the filter residue is distilled to obtain brandy, which is stored for later use. The secondary fermentation temperature is controlled at about 20°C, the fermentation time is 15-20 days; after it ends, the supernatant is taken for aging. (5) Aging. After the raw wine has been stored for 1-2 years, the clear wine is separated out for blending, then fining and freezing treatment are carried out, with a freezing time of 7-10 days; filter while cold, then store for 30 days, after which filtration, sterilization, filling and sealing can be carried out.

3. Characteristics of the finished product: The wine liquid is bright yellow, clear and transparent, with a rich fruity aroma and mellow aroma, suitably sweet-and-sour, mellow and supple, full-bodied, with a long finish, and uniquely characteristic. The volume fraction of alcohol is about 15%, total sugar 17%, total acid 0.7-0.9%, and volatile acid less than 0.1%.

After the secondary fermentation, the raw wine is distilled to obtain brandy; after blending and adjustment, it undergoes aging, freezing and heat treatment to obtain the finished apricot brandy. The wine body is golden yellow, and the volume fraction of alcohol is about 44%.