5.3 THE EDIBLE OIL INDUSTRY 115 Which Italian regions are big producers of olive oil? There are three techniques of hand harvesting: collection of fallen fruit from the ground; stripping of fruit with half open hands from limbs, making the olives fall into picking bags or onto nets below the tree; beating limbs with large sticks to dislodge fruit, which is collected in nets. Pressing bruising: ammaccatura combing: pettinatura decanting: decantazione droplet: gocciolina fall (AmE): autunno gourmet: di alta qualit , da intenditori grinding: frangitura limb: ramo malaxation: gramolatura milling machine: macina olive mill: frantoio pomace: sansa to release: liberare retail sale: vendita al dettaglio to run through: passare stone-crushed: macinato con mole di pietra stone grinder: macine di pietra 240 Food processing OLIVE OIL PROCESSING The process for making olive oil is relatively simple as it relies on a basic principle: crushing the olives to release the oil trapped inside. The characteristics of olive oil are determined by: the variety of olive, climate , growing conditions, harvesting methods, pressing method. Harvesting Harvesting is the first important step. Olives should be harvested at the right moment of ripeness, when they are changing colour from green to black, so that the concentration of oil in the fruit is high. The harvesting method also has an important effect both on the quality of olives produced for table consumption and on the quality of olive oil. Traditional methods involve combing the olives into nets by hand or hand picking into baskets, although today tree shaking machines or picking platforms are also used. Fruit mechanically harvested has 35% more bruising and three times as many with broken skin as that of handharvested fruit. When the fruit is picked carefully by hand , no injuries to olives may be inflicted. Consequently, free fatty acids levels and peroxide are substantially reduced, and total polyphenol content is increased. Processing Once the olives have been picked, they must be taken to an olive mill as soon as possible (within 48 hours), since their vegetable water content may ferment and their acidity level may climb too high, affecting flavour. The production steps are: Cleaning and washing. After being brought to the mill, the olives are inspected to remove large branches and leaves, and then washed; Grinding. The cleaned olives are run through a milling machine which turns them into a paste. Traditionallymade olive oil is still produced using a stone grinder to mill olives, whereas commercial processors use highvolume metal grinders which can operate continuously; Malaxation. Slow mixing for 20 to 40 minutes allows small oil droplets to combine into bigger ones: the correct procedure will ensure the ultimate uniformity of the oil; Pressing. After mixing, the olive paste is put under pressure to extract the liquid oil along with water from the fruit, leaving the paste or pomace behind; Separation and bottling. The olive oil is separated from water, usually with a centrifugal machine or by means of natural decanting. Finally, the olive oil is poured into a steel container where it will be stocked in a dark, cool place before bottling.