Ultrasonic Assisted Extraction of Polyphenols From Apple Pomace

China has rich apple resources, is also the largest producer of concentrated apple juice, resulting in a huge amount of fresh fruit slag, these fruit slag in addition to a small amount of feed, most of the waste. Apple polyphenols are a kind of natural products with biological activity, mainly concentrated in the peel and seed, and entered into the residue with the 

peel during the juicing process, which has been proved to have strong antioxidant activity, and has a variety of pharmacological functions such as antibacterial and anti-inflammatory, prevention of coronary heart disease, anti-tumor, liver protection and anti-cancer. Therefore, the extraction of polyphenols from apple pomace is a scientific measure to make full use of resources.

Fruit and vegetable juice has become one of the most important agricultural industries in the world, and a lot of by-products - fruit and vegetable residue will be obtained in the processing and production of fruit and vegetable juice. As one of the important daily drinks, apple juice production and processing plays an important role in juicing industry, so the output of apple residue also occupies an important proportion in fruit and vegetable residue. Dried fruit residue is mainly composed of dietary fiber and other functional substances, the current apple residue resources have not been fully developed and utilized, but is used as feed, or as garbage, which not only causes a great waste of resources, but also causes pollution to the environment, does not meet the requirements of the sustainable development concept of today's society. In view of the above situation, in this paper, polyphenols and hemicellulost were extracted from apple residue by step extraction method supplemented by ultrasonic technology, and the physicochemical properties of the extracts were preliminically analyzed. This experiment aims to provide theoretical and experimental basis for improving the utilization rate of apple residue resources and increasing the added value of apple juice processing industry.

At present, the extraction of polyphenols from apple residue mostly adopts ultrasonic, microwave, biological enzymatic hydrolysis, ultra-high pressure, supercritical and other auxiliary methods, among which ultrasonic extraction technology uses its cavitation effect, mechanical effect and thermal effect to increase the penetration of the medium and accelerate the dissolution of active substances. Because of its simple operation and high extraction rate, it is widely used, but its disadvantage is that it takes a long time. In recent years, the decompression extraction method has been proposed, which is mainly used in the extraction of traditional Chinese medicine. By vacuuming, the decompression extraction method reduces the oxidation and degradation of heat-sensitive active substances caused by increasing temperature, and makes the system more active, thus speeding up the extraction rate. Therefore, the two methods of ultrasonic and decompression are coupled to improve the extraction rate of natural active substances and protect the active substances from destruction. At present, the extraction of tea polyphenols, jujube peel polyphenols and homouronitine by decompression coupled ultrasonic method has been applied to the research, but it has rarely been applied to the extraction of apple polyphenols. This study mainly used Shaanxi Red Fuji apple residue as raw material, ethanol solution as solvent, optimized the extraction process of polyphenols from apple residue by vacuum (vacuum) coupled ultrasonic wave by response surface method, and analyzed the composition and antioxidant activity of polyphenols by high performance liquid chromatography, in order to provide scientific reference for better and more systematic development and utilization of apple residue resources.

Polyphenols were extracted from Hanfu apple residue by ultrasonic-assisted method with a certain concentration of ethanol solution as extraction agent. The regression equation of polyphenols in apple residue was obtained by response surface method through single factor test analysis of ethanol concentration, ultrasonic power, ultrasonic time and solid-liquid ratio. The optimum extraction conditions of polyphenols were determined as ethanol concentration 49%, ultrasonic power 370 W, action time 136 s and solid-liquid ratio 1:30(g:mL). The actual average extraction yield was 1.71 mg/g.

What’s the princeple of ultrasonic extraction?

Ultrasonic homogenization is the use of ultrasonic cavitation in liquids and other physical effects to achieve homogenization. Physical action refers to the formation of an effective agitation and flow disrupting medium in the liquid, the pulverizing of the particles in the liquid, mainly the collision between the liquid, the micro phase flow and the shock wave leading to changes in the surface morphology of the particles.

Cavitation refers to the generation of holes (small bubbles) in the weaker part of the liquid under the action of ultrasonic waves. The small bubbles pulsate with the ultrasonic waves, and the holes collapse in one sound cycle.

Advantage

1. Core parts with Titanium materials

2. Ultrasonic horn with different size and type for selection

3. Matching with digital generator, auto-tuning, auto search frequency

4. With automatic alarm protection, easy to operate

5. Power adjustable from 1% to 99%

6. Amplitude stability, long working hours, radiation area is increased 2.5 times than
traditional tools

7. Provide consulting services and custom reactor designs

8. Custom sizes available for laboratory and high volume industrial applications.

Application

Food processing Reaction Acceleration
-cavitation accelerates chemical and physical reactions.

Fine Particle Dispersion
-nanoparticle processing

Disruption and Cell Lysing
-will break open biological tissues and Cells to extract enzymes and DNA, prepare vaccines.

Homogenization
-making uniform mixtures of liquids or liquid suspensions.

Emulsification
-processing foods, pharmaceuticals, and cosmetics.

Dissolution
-dissolving solids in solvents.

Degassing
-removing gases from solutions without heat or vacuum.

Inline pipe cleaning
-removes scale or build/up without disassembly.Cylindrical 360° internally radiating chamber.