Bi Xiufang, Hemar Yacine, Balaban Murat O, Liao Xiaojun
College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
School of Chemical Sciences, University of Auckland, 23 Symonds Street, Auckland 1010, New Zealand.
Ultrason Sonochem. 2015 Nov;27:567-575. doi: 10.1016/j.ultsonch.2015.04.011. Epub 2015 Apr 13.
The effect of ultrasound treatment on particle size, color, viscosity, polyphenol oxidase (PPO) activity and microstructure in diluted avocado puree was investigated. The treatments were carried out at 20 kHz (375 W/cm(2)) for 0-10 min. The surface mean diameter (D[3,2]) was reduced to 13.44 μm from an original value of 52.31 μm by ultrasound after 1 min. A higher L(∗) value, ΔE value and lower a(∗) value was observed in ultrasound treated samples. The avocado puree dilution followed pseudoplastic flow behavior, and the viscosity of diluted avocado puree (at 100 s(-1)) after ultrasound treatment for 1 min was 6.0 and 74.4 times higher than the control samples for dilution levels of 1:2 and 1:9, respectively. PPO activity greatly increased under all treatment conditions. A maximum increase of 25.1%, 36.9% and 187.8% in PPO activity was found in samples with dilution ratios of 1:2, 1:5 and 1:9, respectively. The increase in viscosity and measured PPO activity might be related to the decrease in particle size. The microscopy images further confirmed that ultrasound treatment induced disruption of avocado puree structure.
研究了超声处理对稀释鳄梨泥的粒径、颜色、粘度、多酚氧化酶（PPO）活性及微观结构的影响。处理在20 kHz（375 W/cm(2)）下进行0 - 10分钟。超声处理1分钟后，表面平均直径（D[3,2]）从初始值52.31μm降至13.44μm。超声处理后的样品具有更高的L(∗)值、ΔE值和更低的a(∗)值。鳄梨泥稀释呈现假塑性流动行为，超声处理1分钟后，稀释比例为1:2和1:9的稀释鳄梨泥在100 s(-1)时的粘度分别比对照样品高6.0倍和74.4倍。在所有处理条件下，PPO活性均大幅增加。稀释比例为1:2、1:5和1:9的样品中，PPO活性分别最大增加了25.1%、36.9%和187.8%。粘度增加和测得的PPO活性增加可能与粒径减小有关。显微镜图像进一步证实超声处理导致鳄梨泥结构破坏。
