Influence of lupin and chickpea flours on acrylamide formation and quality characteristics of biscuits

Asparagine and sugars are direct precursors of acrylamide; however, proteins and fibres can also influence it. In this study, biscuits prepared replacing wheat flour with increasing concentrations (20, 40, 60%) of lupin or chickpea flour were investigated. Asparagine concentration was equalized in all formulas to isolate the effect of other flour characteristics on the acrylamide formation during baking. The results showed that replacing wheat flour with lupin flour increased acrylamide from 583.9 up to 1443 µg/kg after 9 min of baking, while 20-40% chickpea flour reduced acrylamide to 354.4-312.6 µg/kg. The acrylamide reduction using chickpea was attributed to the lower interaction between precursors resulting from both the coarser particle size and the lower reactivity of carbohydrate in presence of chickpea proteins. Chickpea addition did not affect the colour and texture of biscuits, opening the possibility for large-scale implementation of this mitigation strategy in formulas with a similar initial asparagine content

Selected chemical and physico-chemical properties of ultrasound-assisted osmodehydrated kiwifruit.

Ultrasounds are air vibrations and they generate a rapid series of compression and expansion, having an increasing effect on mass diffusion when combined with osmotic dehydration process (OD). The aim of this work was to investigate the effect of ultrasound (US) pretreatment on the texture, color, chlorophyll content, water activity and thermal properties in terms of freezable water content of osmotic dehydrated kiwifruit. Kiwifruits slices (10 mm thick) were subjected to ultrasonic waves in the bath at a frequency of 35 kHz for 10, 20 and 30 minutes. The osmotic dehydration was carried out by immersion of the samples in 61.5% sucrose solution equilibrated at 25°C for pre-established contact period of 0, 10, 20 and 30 min. The results showed that ultrasound pre-treatment by itself caused a lowering of the kiwifruit firmness in comparison with untreated sample. However 120 minutes after OD treatment the increase of the firmness parameter occurred, which was associated with a greater loss of water during the osmotic dehydration. Moreover there was noticed almost unchanged chlorophyll content in kiwifruit treated with ultrasound compared to fresh sample. During all OD processes the loss of chlorophyll content was observed, however lower for the US pre-treated samples. These data were in agreement with the colour changes observed in kiwifruit samples. Similarly, with increasing time of OD process a decrease of water activity and freezable water content in kiwifruit tissue was observed. In conclusion it can be said that the application of US pre-treatment has a positive effect on different kiwifruit characteristics, particularly in colour and chlorophyll retention

Simple and efficient approach for shelf-life test on frozen spinach and parsley

open6noA simple test for shelf-life assessment of frozen spinach and parsley is presented. A specific shelf-life test that considers three storage temperatures is proposed to accelerate the rate of quality decay in frozen spinach and parsley. The scope was to provide a reliable and rapid way (one month vs years) to predict shelf-life by using a simple experimental approach and mathematical models based on some physical quality product attributes. Physical properties were evaluated at three storage temperatures: -5 degrees C, -10 degrees C and -26 degrees C, to simulate a possible thermal abuse. Mechanical and thermal indexes were defined measuring maximum compression force (N) and latent heat involved in ice melting (J/g). A zeroorder kinetic model was used to properly fit experimental data and thus to obtain related reaction rates. The determination coefficient indicates that there is a strong linear relation between kinetic parameters at -10 degrees C or -5 degrees C and -26 degrees C. This suggests a reliable procedure for shelf-life estimation, carrying out a test at -10 degrees C or -5 degrees C for one month and extending values to data acquired at 26 degrees C for the same period of time. The relations obtained from this research have led to a simple practical approach: one day at -10 degrees C could be considered roughly equivalent to 30 days at -26 degrees C. Accordingly, it could be possible to obtain a shelf-life estimation in short time, also considering other similar products.openIaccheri, Eleonora; Cevoli, Chiara; Romani, Santina; Dalla Rosa, Marco; Molari, Giovanni; Fabbri, AngeloIaccheri, Eleonora; Cevoli, Chiara; Romani, Santina; Dalla Rosa, Marco; Molari, Giovanni; Fabbri, Angel

Ultrasound assisted osmotic dehydration of organic cranberries (Vaccinium oxycoccus): Study on quality parameters evolution during storage.

Cranberries are appreciated for their high amount of antioxidants such as flavonoids, anthocyanins,phenolic acids, carotenoids and vitamins. However, due to their sour and tart taste they request to beprocessed into sweeter dried fruits in order to be acceptable for the consumers. The aim of this work wasto analyse the effect of ultrasound assisted osmotic dehydration on mass transfer parameters and onquality characteristics during storage of cranberries. Ultrasound treatment was performed at the fre-quency of 21 kHz for 30 min in three osmotic solutions - 61.5% sucrose, 30% sucrose with an addition of0.1% of steviol glycosides and 40% trehalose on cut in half cranberries. Afterwards, the cranberry sampleswere subjected to osmotic dehydration process at 40C for 72 h. The osmodehydrated samples both withor without ultrasound pre-treatment were collected and stored at 10C in climatic chamber in micro-perforated plastic bags (PLA) for 8 weeks. The weight reduction, dry matter, water activity, colour, andmicrobiological analysis were performed after 1, 2, 4 and 8 weeks of storage. The obtained resultsindicated that ultrasound application significantly affected the mass transfer parameters during osmotictreatment, as well as it did the type of osmotic solution used. Thermal analysis showed variations insugar melting temperature and enthalpy as a result of osmotic treatment and storage. During the storage,lower weight loss and higher lightness were observed in US pre-treated samples. The sample thatpreserved the best chemico-physical and microbiological characteristics during storage was the onetreated with 61.5% sucrose solution, due to its lowest water activity

Effect of pulsed electric field pre-treatment on microstructure and internal transport throughout osmotic treatment of organic kiwifruit.

Plant cellular structure could be considered a complex organized system where flows are carried out by different solutes or solvents transports systems. Passive transports, which is based on the free energy gradients, involve symplastic, apoplastic and aquaporins transmembrane transports. During osmotic dehydration (OD) treatment the semipermeable membranes such as plasma membrane and tonoplast, are forced to separate, due to the water losses from the vacuoles, starting the process known as plasmolysis, characterized by the loss of the turgor pressure. In the last years, OD has been extensively studied for the partial dehydration of fruits and vegetables in order to obtain semi-moist products; however, it presents some limitations such as the low dehydration rate and the high solute content in the final product. Therefore, the use of pre-treatment such as Pulsed Electric Fields (PEF) has been reported to facilitate water removal and to improve the quality of the dried or osmo-dried products. PEF is a non-thermal technology which involves the application of short and repeated voltage pulses to a biological tissue placed between two electrodes; it induces changes and reorganization in the electric conformation of the cell membrane, modifying the normal fluxes during drying process when it is used as a pre-treatment. In present work PEF has been applied as a pre-treatment prior OD of organic kiwifruits (Actinidia deliciosa cv Hayward) in order to evaluate its effect on the internal structure and internal water transport. PEF pre-treatments were performed using the following parameters: E= 100, 250 and 400 V/cm, 60 near-rectangular shape pulses, pulse width of 100 ± 2 μs and a repetition time of 10.0 ± 0.1 ms. The OD was carried out by immersing the samples in 61.5% sucrose solution at 25 °C for different time period (0-120 min). The samples were analyzed in terms of microstructure by Cryo-SEM microscopy and internal water transport by Time Domain Nuclear Magnetic Resonance (TD-NMR). The results showed that the application of a PEF pre-treatment before the OD produces a process of plasmolysis proportional to the electric field strength applied. It is because the PEF removes the mobile charges of the medium, such as electrolytes, organic acids, amino acids; Ca+2 is the major culprit of the plasmolysis because it fixes some of the junctions of the microtubules between the cell wall and the membrane. In addition, the process of plasmolysis induced by the electric field changes the behavior of kiwifruit tissue during the OD process. In a standard OD without any pretratment, the main transport is the symplastic, whereas if previously treated with PEF, the apoplastic transport is as important as the symplastic, considerably increasing the rate of dehydration. Acknowledgements: Financial support for this project is provided by funding bodies within the FP7 ERA-Net CORE Organic Plus, and with cofounds from the European Commission (No 618107)