Ultrasound-Assisted Extraction of Polyphenols from Crude Pollen

Abstract

The aim of this study was to evaluate the extraction efficiency of polyphenols from crude pollen by an ultrasonic process. Prior to the polyphenols extraction, the crude pollen was defatted. The extraction from defatted pollen was carried out by varying four extraction parameters: ultrasonic amplitude (20%, 60% and 100%), solid/liquid ratio (10 g/L, 20 g/L and 30 g/L), temperature (35, 50 and 65 °C) and time (10, 20 and 30 min). The extracts were analyzed in terms of extraction yield (%), total phenolic content (TPC) and total flavones content (TFC). The extracted oil was analyzed in terms of fatty acids composition; myristic acid (159.1 µg × g−1) and cis-14-pentadecenoic acid (106.6 µg·g−1) were found in the highest amount in the pollen oil. The optimum conditions of extraction were determined and were, as follows: 100% amplitude of ultrasonic treatment, 30 g/L solid/liquid ratio, 40.85 °C and 14.30 min, which led to the extraction of 366.1 mg GAE/L of TPC and 592.2 mg QE/g of TFC, and also to an extraction yield of 1.92%.

Bee Bread: Physicochemical Characterization and Phenolic Content Extraction Optimization

“…The ultrasonic amplitude had a positive influence on the extraction of TFC ( p < 0.01), while for TPC and extraction yield, this process parameter had no significant influence ( p > 0.05). Beebread is considered an important source of flavonoids [ 8 ] and the increase of the cavitation effects of ultrasound may increase the extractability of these compounds [ 33 ]. In the scientific literature, there are some papers reporting on the positive outcome of the use of ultrasounds for the extraction of different bioactive compounds from Nepheliumlappaceum [ 45 ], crude pollen [ 33 ], eggplant peel [ 46 ], grape seeds [ 47 ], as well as tea [ 32 ] and Acer truncatum leaves [ 48 ].…”

“…Beebread is considered an important source of flavonoids [ 8 ] and the increase of the cavitation effects of ultrasound may increase the extractability of these compounds [ 33 ]. In the scientific literature, there are some papers reporting on the positive outcome of the use of ultrasounds for the extraction of different bioactive compounds from Nepheliumlappaceum [ 45 ], crude pollen [ 33 ], eggplant peel [ 46 ], grape seeds [ 47 ], as well as tea [ 32 ] and Acer truncatum leaves [ 48 ]. The increase of the extraction of TFC is due to the cavitation process generated by the ultrasound waves (24–50 kHz) which involve the cavitation bubbles formation and collapse in the media.…”

“…The supernatant was filtered through a 0.45 µm nylon filter. The fatty acids separation and quantification was made on a GC-MS instrument from Shimadzu (GC MS-QP 2010 Plus, Shimadzu, Kyoto, Japan), based on the method described by Oroian et al [ 33 ]. The composition of fatty acids was determined using calibration curves for each fatty acid using FAME’s mixed (Restek, Lisses, France) expressed as µg/g bee bread and as relative level (%) in fatty acids composition.…”

“…The explosion increases the pressure on the cell structure leading to its disruption and the targeted compounds from the matrix pass into the solvent [ 26 , 27 , 28 , 29 ]. Ultrasonic waves have been used in the last years for the extraction of different compounds such as pectin from apple pomace [ 30 ], anthocyanins and phenolic compounds from eggplant peel [ 31 ], polyphenols from old tea leaves [ 32 ], polyphenol from hemp, flax and canola seed cakes [ 26 ], flavonols from pollen [ 33 ], and in all the cases, an increase of extraction efficiency was reported.…”

“…Compared to central composite design, the BBD is much easier to realize because it requires less factor levels. BBD was used for the optimization of different processes such as the extraction of phenolics from eggplant peel [ 31 ], pectin from apple pomace [ 30 ], phenolic compounds from coffee waste [ 34 ], pectin from mango peel [ 35 ], phenolics from bee pollen [ 33 ].…”