Ultrasound enhanced aqueous extraction from rapeseed green biomass for polyphenol and protein valorization

AbstractThe objective of this study was to investigate the effects of ultrasound-enhanced aqueous extraction on the valorization of polyphenols and proteins from rapeseed green biomass. Two types of biomass were studied: mature rapeseed stems collected around the time of seed harvest, and immature rapeseed stems used as a cover crop. Response Surface Methodology (RSM) was employed for obtaining optimal extraction conditions: ultrasound power of 400 W, treatment time of 50 min, sample length of 0.5 cm and agitation speed of 250 rpm. Compared to mature rapeseed stems, immature rapeseed stems require shorter treatment time (30 vs. 50 min), and exhibit higher extraction yield of polyphenols (100 vs. 86%) and proteins (18 vs. 11%) due to their less fibrous structures. These promising findings are opening doors to a potential market for rapeseed stems as a renewable biomass

A versatile simulator for defrosting, convective and boiling drying during hot air frying process

International audienceA versatile simulator takes into account four major stages: defrosting, warm-up, and convective and boiling drying. This dynamic model considers that a frozen prefried french fries has three compartments: a central compartment (#1) with high water content, a peripheral compartment (#3) corresponding to the prefried dry crust, and an intermediate compartment (#2) appears during frying, filled with water vapour. Convective and boiling drying and freezing are modeled. The predicting model has been identified based on the triplicates of three different modalities. The resulting predictions have been experimentally validated

Multi-compartment model for heat and mass transfer during the frying of frozen pre-fried french fries

International audienceThis paper develops a model for hot-air frying of frozen pre-fried french fries. A dynamic threecompartment model including heat and vapour transfer was developed. The model takes into account four major stages: defrosting, warm-up, convective drying and boiling drying. X-ray microtomographic observations led to the assumption of a compartmental structure: a central compartment (#1) with a high water content, a peripheral compartment (#3) corresponding to the dry crust and an intermediate compartment (#2) filled with vapour which appears during frying. The model was validated against experimental measurements: french fries core temperature, and average water content. Validations were made on three different hot-air frying conditions (combining convection and radiation). Heat transfer coefficient (ranging from 66-76 W•m −2 •K −1) and water transfer coefficient (ranging from 0.0035-0.0040 m•s −1) were identified. This model represented well enough the behaviour of french fries from defrosting to boiling drying to be used as a performant numerical tool to control and optimize hot-air frying

A versatile simulator for defrosting, convective and boiling drying during hot air frying process

International audienceA versatile simulator takes into account four major stages: defrosting, warm-up, and convective and boiling drying. This dynamic model considers that a frozen prefried french fries has three compartments: a central compartment (#1) with high water content, a peripheral compartment (#3) corresponding to the prefried dry crust, and an intermediate compartment (#2) appears during frying, filled with water vapour. Convective and boiling drying and freezing are modeled. The predicting model has been identified based on the triplicates of three different modalities. The resulting predictions have been experimentally validated

Microstructure analysis of crust during deep-fat or hot-air frying to understand French fry texture

International audienceThis study aimed to identify the microstructural parameters of the crust which can explain the crispness of French fries. The French fry microstructure was visualized by X-ray micro-computed tomography (XMT). Analysis of the images provided information on the pore size distribution, global porosity of the French fries and local porosity of the crust region. The results revealed that prefrozen French fries do not practically undergo any volume shrinkage during frying. The total porosity created in French fries corresponds to the volume of water loss during frying. The difference between hot-air fried and deep-fat fried French fries was mainly related to the pore diameter and pore size distribution in the crust. Principal component analysis between the sensory and morphometric parameters showed that the volume of small pores (diameter 0.85, P value < 0.05). Thus, a French fry is crispier if the pores generated in the crust have a small median diameter (diameter < 0.2 mm), as well as a large dispersion of pore diameters

Assessment of acoustic-mechanical measurements for texture of French fries: Comparison of deep-fat frying and air frying

International audienceThe aim of this study was to develop an instrumental method for measuring the texture of French fries and correlated it with sensory measurements. For seven samples of French fries with different crispness levels, a cone penetrometer test was conducted simultaneously with microphone recording of sound emissions. A descriptive sensory analysis was also performed on these samples. The results showed that the number of sound peaks, the linear distance of sound peaks, the area under the sound-displacement curve and the mean sound pressure were strongly positively correlated (r ≥ 0.80; P-value < 0.02) with the crispness of the crust descriptor. The number of force peaks and the linear distance of the force peaks were correlated with all the acoustic parameters. These two mechanical parameters and the maximum force, were not correlated with crispness of the crust (r = 0.50; P-value < 0.05) but strongly correlated with product hardness (r = 0.9; P-value < 0.01). However, the combination of the acoustic and mechanical parameters appeared suitable for measuring the texture of French fries. An analysis of the variable importance by random forest showed that the main parameters for quantifying the texture differences were the number of sound peaks and the maximum force. The use of this instrumental method and sensory analysis showed that the deep-fat fried products were crispier than the air fried products with the same water loss