Improvement of the polyphenol extraction from avocado peel by assisted ultrasound and microwaves

Abstract

Ultrasound (UAE) and microwave (MAE) are green technologies to assist in the extraction of polyphenols. The goals were to study the application of sonication temperature (40–60°C), time (15–60 min), microwave power (250–750 W) at 30–120 s; and to combine the principal factors of each method for the maximum recovery of total phenolics from avocado peel employing a response surface methodology. The phytochemical, biological, and feasibility characteristics of the hydroethanolic extracts were analyzed. The combination of 15 min of sonication followed by 95.1 s of microwaving were the optimal parameters to recover 166.3 ± 4.9 mg GAE/g dry matter, which was 1.3, 1.2, and 1.1 times higher than UAE, MAE, and maceration, respectively. Likewise, the U‐MAE was upper in yield (25.3 ± 0.6%), TPC (281.4 ± 0.2 mg GAE), TFC (62.0 ± 0.4 mg QuE), and TAC (4.8 ± 0.1 mg cyanidin‐3‐O‐glucoside) and DPPH, FRAP and LPO (779.1 ± 0.6, 167.0 ± 2.3 μg TEAC, 70.03 ± 0.62%, respectively) per gram of dry extract. All the extracts displayed antibacterial activity. The economic feasibility analysis indicated MAE to be highly effective when energy is less affordable, whereas, if the cost associated with the raw material is high, the U‐MAE is suitable. Practical Applications The extraction industry is moving fast into sustainable processes based on the implementation of ecologically friendly methods of extraction and the utilization of by‐products to obtain bioactive metabolites to be used in the food and pharmaceutical industries. The results here presented were meant to design efficiently extracting procedures. Hence, the correct selection of factors that affect the extraction such as sonication temperature as well as microwave power is vital to reduce the resource consumption; especially raw material and time. Moreover, the exploitation of by‐products as the avocado peel will reduce the negative impact on the environment and enhance the value chain of avocado production.

Fractionation and Hydrolyzation of Avocado Peel Extract: Improvement of Antibacterial Activity

“…Avocado peel is considered to be an excellent source of phenolic compounds to substitute for chemical antioxidants and antimicrobials [ 3 , 32 ]. The raw APE and further fractionation and hydrolysis process led to a change in the TPC, PAC, and antioxidant activity ( Table 2 ).…”

“…The peels from avocado Hass ( Persea americana Mill) were obtained from small-sized avocado fruits from the north part of Chile, according to a previous characterization [ 85 ]. Then, an hydroethanolic avocado crude extract was obtained by the optimal condition of the ultrasound–microwave combined method developed in our previous work [ 3 ]. There were mixed 1 g of the dry avocado peel with 25 mL of solvent (80% ethanol and distilled water).…”

“…Such bacterial forms are responsible for multiple outbreaks with several negative repercussions on human health and the economy [ 1 ]. Hence, the concerns about foodborne illnesses and the possible adverse effect of synthetic preservatives added to food opened the door to incorporating plant extracts high in phenolic compounds (PCs) obtained from fruit by-products such as avocado peel [ 2 , 3 ]. These biomolecules are commonly categorized into two groups: non-flavonoids (phenolic acids, stilbenes, and lignans) and flavonoids (flavones, flavanols, flavanones, anthocyanidins, isoflavones, flavonols, and proanthocyanidins) [ 2 , 4 , 5 ].…”

“…Selectivity and moderate ABA characterize the APE, though the antioxidant activity is high. Our previous work demonstrated the effect of the eco-friendly extraction methods on the biological activity (antioxidant and antimicrobial) of hydroethanolic APE [ 3 ]. The results indicated considerable inhibition of Bacillus cereus (B. cereus) , moderate (MIC ≤ 1000 µg/mL) activity against Escherichia coli (E. coli) , Staphylococcus aureus (S. aureus) , Salmonella spp., Listeria monocytogenes (L. monocytogenes) .…”

Enhanced conditions to obtain a clarified purple araça (Psidium myrtoides) fruit extract

“…Production of dietary supplements or nutraceuticals, food ingredients and pharmaceutical and cosmetic products from natural sources requires the extraction process as a first step (Rico et al, 2020). The extraction efficiency is influenced by several factors, such as extraction time, pH, temperature, solid-to-liquid ratio, and others (Benmeziane et al, 2014;Bindes et al, 2019;Borges et al, 2011), in addition to the application of nonconventional techniques such as microwave and ultrasound assisted extraction processes (Trujillo-Mayol et al, 2019;Vivek et al, 2019). Mathematical modeling of extraction kinetics is an important task to determine the effects of process parameters on extraction yield.…”