Patulin in apples

Patulin is viewed as a natural contaminant in apple-based products, particularly apple juice and unfermented apple cider. It was first isolated from Penicillium griseofulvum in 1943 by Harold Raistrick.

Initially identified as a broad-spectrum antimicrobial agent, patulin was reclassified as a mycotoxin in the 1960s because of its acute toxicity in human beings.

People get exposed to Patulin mainly through consuming infected food products. Fruit contamination might occur at different stages, including in field, during harvesting, at post-harvesting, during transportation, in stores, during display and throughout the processing stages if the produce is not sold raw.

Patulin is a mycotoxin found in apples and is produced by certain species of Aspergillus, Penicillium, and Byssochlamys.

Frequently found in the rotten tissues of apples, patulin accumulation correlates with apparent symptoms of blue mold. Patulin can also occur in various mouldy fruits, grains and other foods. Major human dietary sources of patulin are apples and apple juice made from affected fruit.

The presence of blue mould is generally a good indicator that patulin is present in the fruit. The fungus infects fruit that is wounded or damaged, for example, by insects, bruising or hail.

Apple blue mold usually starts with the invasion of P. expansum spores on the wounds of fresh apples. Such stem punctures, insect injuries, and bruises are created during the picking and handling operations in the apple orchard, until the final processing steps of products.

According to the World Health Organization, the maximum acceptable level of Patulin is set at 50 μg/L in apple juice, 50 μg/kg in solid apples, and 10 μg/L in kids and baby apple-based foods.
Patulin in apples

Sources of pectin

Pectin is a complex carbohydrate component found in the middle lamella of plant cells. Pectins are polyuronides and consist of mixture of pectic substances like protopectin, pectin, pectinic acid and calcium pectate. Pectins with a high molecular weight and a high proportion of methyl ester groups have the best jelly ability.

The pectin content of fruits is variable and depends not only on the type of fruit but also on its maturity or ripeness. Under certain conditions, in presence of sugar and acid, it forms jelly like mass. If jellies or jams are made at home, it is best to add commercial pectin to ensure that there is sufficient pectin to form a gel.

The levels of pectin vary for the different plant tissues; apple pomace, sugar beet pulp., and sunflower heads are major sources of this fiber, ranging in pectin concentration from 15 to 25 g/100 g.

Purified pectin is made from apple cores and skin (apple pomade) and from the white inner skin (albedo) of citrus fruits. It is available in either liquid or granular form. The granular products have a longer shelf life than the liquids.

Pectin also has been manufactured from citrus peel for more than 50 years. All citrus contains pectin and the richest sources are limes, lemons, oranges and grapefruit in decreasing importance.

The soft, white spongy layer called albedo, just under the colored portion of the peel is the principle source of pectin.

Low-methyl pectin can be obtained by demethylating pectin with enzymes, acid or alkali until it is 20-40 % esterified.

Since these pectins gel with divalent ions and need no sugar, they can be used commercially for the production of low-calorie jams, jellies, or desserts.
Sources of pectin