P1: SFK/UKS BLBS102-c27 P2: SFK BLBS102-Simpson March 21, 2012 13:25 Trim: 276mm X 219mm Printer Name: Yet to Come 27 Biochemistry of Fruits Whitaker BD 1991 Changes in lipids of tomato fruit stored at chilling and non-chilling temperatures Phytochemistry 30: 757–761 Whitaker BD 1992 Changes in galactolipid and phospholipid levels of tomato fruits stored at chilling and non-chilling temperatures Phytochemistry 31: 2627–2630 Whitaker BD 1993 Lipid changes in microsomes and crude plastid fractions during storage of tomato fruits at chilling and nonchilling temperatures Phytochemistry 32: 265–271 553 Whitaker BD 1994 Lipid changes in mature green tomato fruit during ripening, during chilling, and after re-warming subsequent to chilling J Amer Soc Hort Sci 119: 994–999 Whitaker BD et al 2001 Cloning, characterization and functional expression of a phospholipase D alpha from tomato fruit Physiol Plant 112: 87–94 Yang SF 1981 Ethylene, the gaseous plant hormone and regulation of biosynthesis Trends Biochem Sci 6: 161–164 P1: SFK/UKS BLBS102-c28 P2: SFK BLBS102-Simpson March 21, 2012 13:54 Trim: 276mm X 219mm Printer Name: Yet to Come 28 Biochemistry of Fruit Processing Moustapha Oke, Jissy K Jacob, and Gopinadhan Paliyath Introduction Fruit Classification Chemical Composition of Fruits Carbohydrates Vitamins Minerals Dietary Fiber Proteins Lipids Volatiles Water Organic Acids Pigments Phenolics Cell Structure Fruit Processing Harvesting and Processing of Fruits Freezing and Canning of Fruits Nonenzymatic Browning Fruit Juice Processing Apple Juice Processing Enzyme Applications Apple Juice Preservation Processed Apple Products Apple Sauce Sliced Apples Dried Apple Products Quality Control Biochemical Composition and Nutritional Value of Processed Apples Flavanones Flavonols Anthocyanins Flavans Further Reading References Abstract: Processing of fruits is an important segment of food industry As fruits are highly perishable, processing is an efficient way of ensuring their year-round availability Fruits are processed into juice, sauce, infused and dried products Several standardized techniques are available to preserve the quality of processed products, still, there are nutrient losses associated with processing Common fruits processed include grape, orange, apples, pears, peach, and so on Processed fruits can be enriched with the addition of nutraceutical components INTRODUCTION Overall, the food and beverage processing industry is an important manufacturing sector all across the world The United States is among the top producers and consumers of fruits and tree nuts in the world Each year, fruit and tree nut production generates about 13% of US farm cash receipts for all agricultural crops Annual US per capita use of fruit and tree nuts totals nearly 300 pounds fresh-weight equivalent Oranges, apples, grapes, and bananas are the most popular fruits The consumption of fruits and processed products has enjoyed an unprecedented growth during the past decade Many factors motivate this increase, including consumers’ awareness of the health benefits of fruit constituents such as the importance of dietary fiber, antioxidants, vitamins, minerals, and phytochemicals present in fruits In food stores, one can buy fresh and processed exotic food items, either canned, frozen, dehydrated, fermented, pickled, or made into jams, jellies, and marmalades year-round Several varieties of fruits are sold throughout the year in developed countries, and with the increase in international trade of fruits, even tropical fruits are available at a reasonable cost The food processing industry uses fruits as ingredients in juice blends, snacks, baby foods, and many other processed food items As a Food Biochemistry and Food Processing, Second Edition Edited by Benjamin K Simpson, Leo M.L Nollet, Fidel Toldr´a, Soottawat Benjakul, Gopinadhan Paliyath and Y.H Hui C 2012 John Wiley & Sons, Inc Published 2012 by John Wiley & Sons, Inc 554 P1: SFK/UKS BLBS102-c28 P2: SFK BLBS102-Simpson March 21, 2012 13:54 Trim: 276mm X 219mm Printer Name: Yet to Come 555 28 Biochemistry of Fruit Processing Table 28.1 World Production of Fruit in 2002 in Metric Tons Production (Metric Tons) Africa Asia Europe America Australia and New Zealand World Primary fruits Apples Bananas Grapes Mangoes Oranges Pears Plums Strawberries 61,934,001 1,696,109 7,140,629 3,113,940 2,535,781 4,920,544 530,547 173,946 171,132 204,640,809 30,870,497 35,766,134 14,761,974 19,841,469 14,177,590 10,996,503 5,385,634 325,670 73,435,847 15,820,454 446,600 28,739,848 – 6,180,846 3,626,020 2,661,194 1,276,192 129,642,621 7,875,880 15,372,622 12,529,900 3,343,697 38,402,953 1,759,538 1,069,953 1,157,540 4,438,090 831,999 250,000 1,872,588 28,000 444,500 202,597 24,000 21,300 475,503,880 57,094,939 69,832,378 61,018,250 25,748,947 64,128,523 17,115,205 9,314,727 3,237,533 Source: Calculated from FAOSTAT database http://faostat.fao.org/default.aspx Accessed on December 07, 2011 result, the world production of primary fruits has increased from 384 million metric tons in 1992 to 475 million metric tons in 2002 (FAO) The world production of fruits in 2002 by regions is shown in Table 28.1 Advances in fruit processing technologies mostly occur in response to consumer demands or improvement in the efficiency of technology Traditional methods of canning, freezing, and dehydration are progressively being replaced by fresh-cut, readyto-eat fruit preparations The use of modified atmosphere and irradiation also helps in extending the shelf life of produce Fruits are essential source of minerals, vitamins, and dietary fiber In addition to these components, they provide carbohydrates, and to a lesser extent, proteins Fruits play an important role in the digestion of meat, cheese, and other high-energy foods by neutralizing the acids produced by the hydrolysis of lipids CHEMICAL COMPOSITION OF FRUITS Carbohydrates Fruits typically contain between 10% and 25% carbohydrates, less than 1% of protein and less than 0.5% of fat (Somogyi et al 1996b) Carbohydrates, sugars, and starches are broken down into CO2 , water, and energy during catabolism The major sources of carbohydrates are banana, plantain, date, raisin, breadfruit, and jackfruit Proteins and amino acids are contained in dried apricot and fig, whereas fats are the major components of avocado and olives Sugars are the major carbohydrate components of fruits and their composition vary from fruit to fruit In general, sucrose, glucose, and fructose are the major sugar components present in fruits (Table 28.2) Several fruits also contain sugar alcohols such as sorbitol Vitamins FRUIT CLASSIFICATION Fruits can be broadly grouped into three categories according to their growth latitude, whether it is in temperate, subtropical, or tropical regions Temperate zone fruits: Four subgroups can be distinguished among temperate zone fruits that include small fruits and berries (e.g., grape, strawberry, blueberry, blackberry, cranberry), stone fruits (e.g., peach, plum, cherry, apricot, nectarine) and pome fruits, (e.g., apple, pear, Asian pear or Nashi, and European pear or quince) Subtropical fruits: Two subgroups can be differentiated among subtropical fruits and include citrus fruits (e.g., orange, grapefruit, lemon, tangerine, mandarin, lime, and pummelo), and noncitrus fruits (e.g., avocado, fig, kiwifruit, olive, pomegranate, and cherimoya) Tropical fruits: Major tropical fruits include banana, mango, papaya, and pineapple Minor tropical fruit include passion fruit, cashew apple, guava, longan, lychee, mangosteen, carambola, rambutan, sapota, and so on Fruits and vegetables are major contributors to our daily vitamin requirements The nutrient contribution from a specific fruit or vegetable is dependent on the amount of vitamins present in the fruit or vegetable, as well as the amount consumed The approximate percentage contribution to daily vitamin intake from fruits and vegetables is: vitamin A, 50%; thiamine, 60%; riboflavin, 30%; niacin, 50%; and vitamin C, 100% (Somogyi et al 1996b) Vitamins are sensitive to different processing conditions such as exposure to heat, cold, reduced and high levels of oxygen, light, free water, and mineral ions Trimming, washing, blanching, and canning can also cause the loss in vitamin content of fruits and vegetables Minerals Minerals found in fruits in general may not be fully nutritionally available (e.g., calcium, found as calcium oxalate in certain produce is not nutritionally available) Major minerals in fruits are base-forming elements (K, Ca, Mg, Na) and acid-forming elements (P, Cl, S) Minerals often present in microquantities are Mn, Zn, Fe, Cu, Co, Mo, and I Potassium is the most abundant mineral in fruits, followed by calcium and magnesium High potassium is often associated with increased acidity and P1: SFK/UKS BLBS102-c28 P2: SFK BLBS102-Simpson March 21, 2012 13:54 Trim: 276mm X 219mm 556 Printer Name: Yet to Come Part 5: Fruits, Vegetables, and Cereals Table 28.2 Sugar Composition of Selected Fruits Sugar, g/100 mL of Juice Fruit Apple Cherry Grape Nectarine Peach Pear Plum Kiwifruit Strawberry Sucrose Glucose Fructose Sorbitol 0.82±0.13 0.08±0.02 0.29±0.08 8.38±0.73 5.68±0.52 0.55±0.12 0.51±0.36 1.81±0.72 0.17±0.06 2.14±0.43 7.50±0.81 9.59±1.03 0.85±0.04 0.67±0.06 1.68±0.36 4.28±1.18 6.94±2.85 1.80±0.16 5.31±0.94 6.83±0.74 10.53±1.04 0.59±0.02 0.49±0.01 8.12±1.56 4.86±1.30 8.24±3.43 2.18±0.19 0.20±0.04 2.95±0.33 ND 0.27±0.04 0.09±0.02 4.08±0.79 6.29±1.97 ND ND Source: Reprinted with permission from Van Gorsel et al 1992 Copyright, American Chemical Society ND, not detected (