Olive oil processing technology(Part 2)
Olive oil processing technology and technical characteristics
The olive oil processing technology and equipment are relatively simple. The traditional method is to grind the ripe and cleaned olive locust fruit on a stone mill, then pack it in a clean special straw bag, put it on an extruder to squeeze out the oil, filter, settle, and bottle it. Can become refined oil. The modern olive oil processing technology uses a high-speed centrifuge to quickly separate the oil and residue, which effectively improves the oil yield and the quality of the oil.
The olive oil processing technology and equipment are relatively simple. The traditional method is to grind the ripe and cleaned olive locust fruit on a stone mill, then pack it in a clean special straw bag, put it on an extruder to squeeze out the oil, filter, settle, and bottle it. Can become refined oil. The modern olive oil processing technology uses a high-speed centrifuge to quickly separate the oil and residue, which effectively improves the oil yield and the quality of the oil.
1. Modern olive oil processing technology
Fresh fruit collection→transport and storage→cleaning of branches and leaves→grinding→fusion→centrifugal decantation→centrifugal separation→storage→bottling.
2. Technical characteristics
Fresh fruit collection. Due to different varieties, the best collection month is from November to February of the following year. When picking fruits, avoid direct contact with the ground. The oil content of green fruit is low but contains high polyphenol compounds. The oil content of black fruit is high but the antioxidant content is low. Therefore, in order to ensure the oil quality and oil yield, the best ratio of green fruit to black fruit is 75:25 In actual production, the ratio is controlled to be about 50:50.
1) Transportation and storage. The collected fresh fruits should be put into small baskets, stacked and transported to the processing plant, and spread flat in a ventilated storage room to avoid overpressure, overheating and bruising of the fresh fruits, otherwise they are easy to oxidize and ferment. But in actual transportation, hemp bags are used for stacking of fruits, so the stacking time does not exceed 1 to 2 days.
2) Remove branches and leaves. With belt conveying and aspiration, branches and leaves are separated from fruits by fans. The fruit is required to have no leaves, because the leaves contain more chlorophyll. During the process of crushing and fusion, due to the higher temperature, the chlorophyll is easily oxidized and affects the oil quality, so the power of the fan is larger.
3) Cleaning. The purpose is to remove dust and a small amount of leaves. Cleaning requires a certain amount of water, which will produce wastewater. In order to reduce the amount of wastewater, circulating water cleaning is used. The control amount is 2t water to clean 5t fruits.
4) Grind. The hammer crusher is used for crushing. The sieve apertures size and beat speed are the key points. The best sieve apertures diameter is 6mm, and the best beat speed is 2500～3000r/min. The acidity of the oil and the peroxide UV Value, total phenols and sterols have good results.
5) Fusion. The broken fruit pulp is transferred to the fusion pool and mixed uniformly through the movement of the screw rod. On the one hand, it is beneficial to heat dissipation; on the other hand, it is beneficial to the formation of oil droplets and avoids emulsification. Controlling the temperature and mixing time is the key, the best time is 30min, the temperature is less than 40℃, adopt the cooling method of interlayer water flow.
6) Centrifugal decantation. Currently, three-phase centrifugation is mostly used, and a few use two-phase centrifugation. Three-phase centrifugation needs to add 40%-50% water, of which pomace accounts for about 45%, the residual oil rate is 4% to 6%, and the oil yield is about 25%.Two-phase centrifugation does not need to add water, the pomace accounts for about 75%, the water content is 60% to 65%, and the oil yield is about 25%. The centrifuge speed is 3 000r/min.
7) Storage. The centrifuged oil is stored in a large stainless steel storage tank to avoid light and heat, and can be filled with nitrogen if necessary.
8) Bottling. The oil in the storage tank regularly releases a small amount of water and oil sediment. If it is still not clear, it can be mixed with diatomaceous earth and filtered through a plate and frame, and then divided into small bottles.
2. Technical characteristics
Fresh fruit collection. Due to different varieties, the best collection month is from November to February of the following year. When picking fruits, avoid direct contact with the ground. The oil content of green fruit is low but contains high polyphenol compounds. The oil content of black fruit is high but the antioxidant content is low. Therefore, in order to ensure the oil quality and oil yield, the best ratio of green fruit to black fruit is 75:25 In actual production, the ratio is controlled to be about 50:50.
1) Transportation and storage. The collected fresh fruits should be put into small baskets, stacked and transported to the processing plant, and spread flat in a ventilated storage room to avoid overpressure, overheating and bruising of the fresh fruits, otherwise they are easy to oxidize and ferment. But in actual transportation, hemp bags are used for stacking of fruits, so the stacking time does not exceed 1 to 2 days.
2) Remove branches and leaves. With belt conveying and aspiration, branches and leaves are separated from fruits by fans. The fruit is required to have no leaves, because the leaves contain more chlorophyll. During the process of crushing and fusion, due to the higher temperature, the chlorophyll is easily oxidized and affects the oil quality, so the power of the fan is larger.
3) Cleaning. The purpose is to remove dust and a small amount of leaves. Cleaning requires a certain amount of water, which will produce wastewater. In order to reduce the amount of wastewater, circulating water cleaning is used. The control amount is 2t water to clean 5t fruits.
4) Grind. The hammer crusher is used for crushing. The sieve apertures size and beat speed are the key points. The best sieve apertures diameter is 6mm, and the best beat speed is 2500～3000r/min. The acidity of the oil and the peroxide UV Value, total phenols and sterols have good results.
5) Fusion. The broken fruit pulp is transferred to the fusion pool and mixed uniformly through the movement of the screw rod. On the one hand, it is beneficial to heat dissipation; on the other hand, it is beneficial to the formation of oil droplets and avoids emulsification. Controlling the temperature and mixing time is the key, the best time is 30min, the temperature is less than 40℃, adopt the cooling method of interlayer water flow.
6) Centrifugal decantation. Currently, three-phase centrifugation is mostly used, and a few use two-phase centrifugation. Three-phase centrifugation needs to add 40%-50% water, of which pomace accounts for about 45%, the residual oil rate is 4% to 6%, and the oil yield is about 25%.Two-phase centrifugation does not need to add water, the pomace accounts for about 75%, the water content is 60% to 65%, and the oil yield is about 25%. The centrifuge speed is 3 000r/min.
7) Storage. The centrifuged oil is stored in a large stainless steel storage tank to avoid light and heat, and can be filled with nitrogen if necessary.
8) Bottling. The oil in the storage tank regularly releases a small amount of water and oil sediment. If it is still not clear, it can be mixed with diatomaceous earth and filtered through a plate and frame, and then divided into small bottles.
