A survey was conducted by a bunch of scientists in China to analyze the inclination of Chinese consumers toward consuming fruit peels.

Within the research published within the journal Food Research International, the scientists provided reasonable dietary recommendations for consuming fruit peels and discussed the methods of detecting and removing pesticides from fruit peels.

Review: Eating with peel or not: Investigation of the peel consumption situation and its nutrition, risk evaluation, and dietary advice in China. Image Credit: Oxs Fraim / Shutterstock

Background

Fruits are essential to a healthy weight loss program as they contain high amounts of minerals, vitamins, dietary fibers, and other phytochemicals with health advantages. Regular consumption of fruits is understood to cut back the danger of cardiovascular diseases, dementia, age-related diseases, and cancer.

Studies analyzing fruit nutrients have identified fruit peels can often have more dietary value than fruit pulp. Nevertheless, the suitability of fruit peel consumption will depend on various aspects, including nutrient content, amount of pesticide, microbial contamination, ease of peeling, and fruit texture.

The survey explored fruit peel consumption preferences of consumers across 28 provinces in China. The age range of the survey population was 15 – 70 years, with nearly all of participants aged 18-25 years. The survey included three basic questions: preference for consuming fruits with peel, reasons for consuming peels, and aspects influencing peel consumption.

The survey findings concluded that nutrient content and the presence of pesticides are the 2 major concerns of Chinese consumers preferring to eat fruits with peel.

Presence of pesticides

Pesticides are widely utilized in the food industry to enhance the production and quality of fruits, vegetables, and other food products. Nevertheless, direct or indirect consumption of pesticides can have detrimental effects on human health.  

Within the survey, scientists primarily focused on eight sorts of fruits, including apple, grape, pear, peach, kumquat, lemon, melon, and persimmon. Based on the observations made by the scientists, the production of apples, pears, and grapes needs higher amounts of pesticides in comparison with other fruits tested. Nevertheless, based on the Chinese national standard, the quantity of pesticide used for production doesn’t exceed the utmost residue limits for these fruits. In other words, the quantity of pesticide residues present within the pulp and peels of those fruits is well inside the protection limits.

The quantity of pesticide residues in fruit peels was found to be higher than that within the pulp. Nevertheless, in some fruits, including grapes, higher amounts of pesticide residues were present in pulps than in peels.

Given these findings, scientists recommend that country-specific food-quality inspection standards be considered while analyzing the danger of fruit peel consumption based on pesticide content.

Consumption of pesticides can have each short-term (headache and nausea) and long-term (reproductive problems, endocrine disorders, and cancer) health effects. Studies have found that certain fungicides (prochloraz, pyraclostrobin, and tebuconazole) present in pear peel can disrupt endocrine functions, mitochondrial respiration, and steroid biosynthesis. Organophosphate pesticides are known to affect human metabolism and increase obesity risk. DDT is one other insecticide already banned in lots of countries due to carcinogenic activities.

Detection of pesticides

Liquid and gas chromatography are the 2 mostly used methods to detect pesticides in fruit peels.

High-performance liquid chromatography (HPLC) together with tandem mass spectrometry has been found to concurrently detect 22 chiral pesticides and their enantiomeric compositions in vegatables and fruits. Nanoparticles may be introduced in this type of method as matrix solid-phase dispersive extraction sorbents to rapidly detect multiple pesticides in food products with high specificity, sensitivity, and accuracy.  

Gel permeation chromatography Gas chromatography-mass spectrometry (GPC–GC/MS) is one other widely used method to rapidly detect pesticides in fruits. This method includes easy sample preparation procedures, efficiently eliminating matrix interference.

Gas chromatography, together with an electron capture detector, is one other widely used method to detect organochlorine and pyrethroid pesticides in vegatables and fruits. Nevertheless, one drawback of this method is the production of false-positive results.

Removal of pesticides

Washing vegatables and fruits with clean water is probably the most commonly used method to remove pesticides in each day life. Washing food items with tap water has been found to cut back pesticide content by 35-38% on average.

While washing with tap water has been found to cut back pesticide content by 70% from grapes, the identical method has been found to cut back only toluofluoroaniline and no other pesticides from apples. This means that water-insoluble wax on the peel may hinder the removal of some pesticides.     

In comparison with cold water, hot water, saline water, and rice water are considered higher options for pesticide removal. Some chemicals that may be used with water for higher cleansing vegatables and fruits include sodium bicarbonate, ethanol solution, and alcohol solution.  

Some household cleansing machines, including ozone cleansing machines, ultrasonic cleansing machines, and low-temperature plasma cleansing machines, are gaining popularity for pesticide removal from vegatables and fruits.

Dietary value of fruit peels

Apple peel is a wealthy source of flavonoids and phenolic acids. In comparison with apple pulp, apple peel accommodates higher amounts of dietary fibers, minerals, flavonoids and triterpenoids, and other phytochemicals with antioxidant and anticancer properties. 

Pear peel accommodates high amounts of glucose, sucrose, citric acid, malic acid, quinic acid, caffeic acid, arbutin, flavanols, and phenolic acids. These compounds are known to have antioxidant, anti-inflammatory, anti-diabetic, and lipid-lowering properties.  

Peach peel accommodates high amounts of organic acids, vitamins, minerals, dietary fibers, phenolic acids, and flavonoids with high antioxidant and anti inflammatory properties.

Grape peel accommodates high amounts of anthocyanins, tannins, terpenes, nitrogen-containing substances, and fatty acid substances. These compounds have potent antioxidant, anti-inflammatory, and anticancer properties.

Melon peel is a wealthy source of vitamins, dietary fibers, unsaturated fatty acids and their esters, cyclic ketones, aldehydes, anthocyanin derivatives, potassium, calcium, magnesium, and other mineral salts and phenolic compounds. These compounds have antibiotic and anticancer properties.

Lemons and kumquats are citrus fruits and wealthy sources of vitamin C and dietary pectin. Lemon peel extract containing a minimum of 70 sorts of volatile compounds has been found to have a powerful antibacterial effect against Gram-negative bacteria. Kumquat peel can also be a natural source of many bioactive compounds with antioxidant and lipid-lowering properties.  

Persimmon peel accommodates high amounts of vitamins, polyphenols, and tannins. Persimmon peel extract is understood to cut back the danger of hypertension, coronary heart disease, and sort 2 diabetes.

Certain molecules found on fruit peels, including pathogenesis-related 10 (PR-10) proteins and lipid transfer proteins, can induce allergic reactions in some individuals. Peach peel can induce severe, life-threatening allergic reactions in allergic individuals, and immature persimmon can induce abdominal pain.