Polyphenols in apples

Polyphenols represent a group of secondary metabolites with aromatic ring(s) bearing one or more hydroxyl moieties. Polyphenols are powerful antioxidants. They prevent or reverse damage in human cells caused by aging, the environment, and lifestyle. Over time, this damage is linked to an increased risk of many chronic diseases.

Apples contain a variety of phenolic compounds. There are five major groups of polyphenolic compounds found in apples: flavanols (catechin, epicatechin and procyanidins), phenolic acids (mainly chlorogenic acid), dihydrochalcones (phloretin glycosides), flavonols (quercetin glycosides) and anthocyanins (cyanidin).

Apple peels have higher levels of polyphenols than flesh or core and also abundant in flavonoids such as quercetin glycosides and cyanidin galactoside. The flesh and core have relatively high concentrations of chlorogenic acid.

Polyphenols originate from the plant aromatic pathway, starting with amino acids of the shikimate pathway and culminating in molecules produced by the phenyl propanoid and flavonoid pathways. The coordinated induction-regulation of these pathways leads to the production of several thousand different molecules.

The nature and content level of polyphenols present in food sources will be influenced by various factors. For apples, the variety, agricultural practices, harvesting, and if supplementing, the extraction process will be among the factors contributing to polyphenol concentration.

Each polyphenol molecule might have specific health benefits. The non-glycosilated form of phlorizin, phloretin, has been shown to influence epigenetic processes, heritable changes not encoded in the DNA sequence itself that play an important role in gene expression regulation in breast cancer cells.

Apple polyphenols also seem to block fat and cholesterol from entering the body and slow the production of fat and cholesterol. This may allow them to lower cholesterol and help with weight loss.

Apple juice may work in cognitive decline of normal aging suppressing over expression of presenilin-1, which is linked to the production of amyloid β-peptide, a marker of Alzheimer’s.
Polyphenols in apples

Waxing the fruit

Coatings applied to the surfaces of fruits and vegetables are commonly called ‘waxes, whether or not any component thereof is actually a wax. Commodities that are waxed include apples, avocados, citrus, cucumbers, eggplant, peaches, sweet peppers, and tomatoes.

A freshly picked apple is matte with dust. It can be scratched, scarred, and pocked with insect bites. An apple in the store is smooth. It shines.

That grocery-store gloss is artificial fruit wax. The wax added to protect Washington apples is usually carnauba or shellac. Both are approved by the U.S. Food and Drug Administration and have been used on a variety of foods for decades. These wax formulations are natural, non-petroleum based coatings.

Once an apple leaves the orchard, it is sprayed with a commercial coating specially formulated to impress buyers. These smooth sprayed-on coats give a glow to most retail produce—from cantaloupes to avocados to limes.

Research horticulturists from the USDA report "the use of wax on Red Delicious apples improved firmness and color, and reduced weight loss."

Perhaps the most-studied property of waxed fruit is its weight loss during storage. In almost all cases, waxed commodities lost weight more slowly than unwaxed controls. In fact, weight reduction has been recommended as a criterion of good waxing.

California’s Brogdex Company founder, Ernest Brogden, filed the first U.S. patent to cover fruit on a commercial scale, in 1922. Brogden’s original wax-and-kerosene mixture created “a film-like waxy coating that ... maintains the fruit in its original firm, plump, and fresh condition for relatively long periods of time.”

This layer of waxing was of great importance in diminishing water losses from apples. Research has shown that apple waxing enhances firmness retention and slows down the apple respiration rate.

Although the wax used on Washington apples is safe to consume, according the US Food and Drug Administration, it is important to wash all fresh fruits and vegetables before eating.
Waxing the fruit

Processing of Apples

Processing of Apples
For production of apple slices, apples are size graded peeled, cored, sliced and immersed in a 3% salt solution.

Just before filling into cans, the slices are rinsed to remove salt. They are then filled into can with 40% sugar solution, the cans are then heat-exhausted, sealed and heat processed.

For the production of frozen apple slices, there are number of procedures , but basically, the slices are immersed in brine subjected to vacuum (in order to remove air), re-immersed in brine, washed and packed with sugar in a ratio of 4 fruit to 1 sugar, the product is then frozen. One method differs in that a bisulfite dip is included to prevent non enzymatic browning.

Some apples are dried, although the volume of this type of product has decreased in recent years. For drying, the peeled, cored and sliced apples are first treated in a weak solution of citric and a bisulfite dip. The bisulfite provides sulfur dioxide that inhibits enzymatic browning.

The sulfured slices should be held in refrigerated storage for at least 24 hrs to allow the sulfur dioxide to penetrate the apple slices, the apple slices are eventually spread in the slatted floors of natural draft, loft-type kilns. In the kilns, heated air rises through the apples slice and removes moisture.

After the moisture content has reached about 10%, the apples are packaged in moisture proof containers to be used in the bakery trade.
Processing of Apples

Apples

Apples
In United States, apples are grown in practically every state. They are grown commercially in 35 states with the heaviest production taking place in Washington, New York, Virginia, Michigan, California, and Pennsylvania. There are hundreds of varieties of apples that may be grown on trees produced from seedlings that were grown in nurseries, or from grafts on existing apple tree. The fruit is developed on spurs formed by branchlets of three or more years to growth, the tree yielding for many years thereafter. Fertilizer of the soil and periodic pruning and thinning of apple trees are considered necessary for good apple crops.

Apples are used as the fresh fruit, and apples not suitable for fresh fruit are used for the production of juice, cider, sauce, vinegar, jam, jelly, pie filling and as an ingredient in a variety of baked goods. Pectin is extracted from the peels and cores.

After harvesting, the fruit are washed in dilute HCL or NaOH solutions to remove spray residues and are rinsed. Apples are cooled to and stored at 32 degree F until shipped. Increased storage life is attained by reducing the amount of oxygen and increasing the amount of carbon dioxide in the atmosphere around the apples.
Apples