Valorization of Wild Apple (Malus spp.) By-Products as a Source of Essential Fatty Acids, Tocopherols and Phytosterols with Antimicrobial Activity

Abstract

The amplified production of fruit as well as burgeoning demand for plant-made food products have resulted in a sharp increase of waste. Currently, millions of tons of by-products are either being discarded or utilized rather ineffectively. However, these by-products may be processed and further incorporated as functional ingredients in making high-value food products with many physiological and biochemical effects. The chemical analysis of pomace oils using gas chromatography-mass spectrometry (GC/MS) and reversed-phase-liquid chromatography coupled with fluorescence detector (RP-HPLC/FLD) systems led to the identification and quantification of 56 individual lipophilic compounds including unsaturated, polyunsaturated and saturated fatty acids, as well as phytosterols and four homologs of tocopherol. The oils recovered from by-products of Malus spp. (particularly cv. “Ola”) are rich in fatty acids such as linolenic (57.8%), α-linolenic (54.3%), and oleic (25.5%). The concentration of total tocopherols varied among the Malus species and dessert apples investigated, representing the range of 16.8–30.9 mg mL−1. The highest content of total tocopherols was found in M. Bernu prieks, followed by M. cv. “Ola”, and M. × Soulardii pomace oils. A significantly higher amount of δ-tocopherol was established in the oil of M. Bernu prieks, indicating that this species could be utilized as a natural and cheap source of bioactive molecules. β-Sitosterol was the prevalent compound determined in all tested pomace oils with a percentage distribution of 10.3–94.5%. The main triterpene identified in the oils was lupeol, which varied in the range of 0.1–66.3%. A targeted utilization of apple pomace would facilitate management of tons of by-products and benefit the environment and industry.

Beneficial Anti-Platelet and Anti-Inflammatory Properties of Irish Apple Juice and Cider Bioactives

“…These results concerning the fatty acid composition of PL from apple juice and apple cider are in accordance with previously reported ones for lipids from apple juice and cider [22,23], but also in PL from other plant-derived food sources used for beverages products, such as beer and tea [9,17].…”

Bioconversion of Milk Permeate with Selected Lactic Acid Bacteria Strains and Apple By-Products into Beverages with Antimicrobial Properties and Enriched with Galactooligosaccharides

“…It was also reported that the presence of phloretin and its glycosylated derivatives in apples are able to inhibit growth of Gram-positive bacteria, and are active against some strains of the Gram-negative bacteria [ 48 ]. In the research of Radenkovs (2018) [ 49 ] wild apple pomace oil showed inhibitory capacity against both Gram-positive and Gram-negative bacteria strains. These could explain the antimicrobial activity of AppMPNF against Streptococcus epidermis and Streptococcus mutans found din our research data.…”

Highly-Efficient Release of Ferulic Acid from Agro-Industrial By-Products via Enzymatic Hydrolysis with Cellulose-Degrading Enzymes: Part I–The Superiority of Hydrolytic Enzymes Versus Conventional Hydrolysis

“…Each bran sample before EH was defatted following the methodology described by Radenkovs et al [ 25 ] and ground to reach Ø 0.5 mm particle size using a variable speed rotor mill Pulverisette 14 (Fritsch, Idar-Oberstein, Germany). To exclude possible cell-wall disruption by native enzymes and microorganisms that can be localized on the surface of bran, the samples were mixed with double distilled water (DDW) at the ratio of 1:10 ( w / v ), loaded into 25 mL reagent bottles with screw caps (VWR™, International, GmbH, Darmstadt, Germany), and subjected to autoclaving using a digital autoclave with counter-pressure (Raypa, AES 110, Barcelona, Spain) for 10 min at 121 ± 1 °C temperature and counter pressure 2.0 Pa.…”