Comparative study of six pear cultivars in terms of their phenolic and vitamin C contents and antioxidant capacity

The main phenolic compounds in six pear cultivars were identified and quantified using high-performance liquid chromatography/diode array detection (HPLC/DAD) and HPLC/electrospray ionisation mass spectrometry (HPLC/ESIMS). Major quantitative differences were found in the phenolic profiles. The peel contained higher concentrations of chlorogenic acid, flavonols and arbutin than the flesh, where only chlorogenic acid was detected. Total phenolics ranged from 1235 to 2005mgkg−1 in the peel and from 28 to 81mg k g−1 in the flesh. Ascorbic acid and dehydroascorbic acid were detected in the peel, whereas only dehydroascorbic acid was present in the flesh. The ranges of vitamin C content were from 116 to 228mg kg−1 in the peel and from 28 to 53mg kg−1 in the flesh. The antioxidant capacity was correlated with the content of chlorogenic acid (r = 0.46), while ascorbic acid made only a small contribution to the total antioxidant capacity of the fruit

Effects of preharvest, harvest and postharvest factors on the quality of pear (cv. "Rocha") stored under controlled atmosphere conditions

Pears (cv. Rocha’) grown at two locations and picked up at various times during the harvest season were assessed for firmness and colour, following 9 mo of storage under air or under controlled atmosphere conditions. A second-order polynomial was able to accurately fit the effect of time of harvest on pear’s quality, in an essentially empirical modelling effort; the best estimates of the parameters therein depend on the growing location, as well as on the atmosphere gas composition prevailing during storage

Sensorial and physicochemical quality responses of pears (cv Rocha) to long-term storage under controlled atmospheres

Pears (cv Rocha) kept under controlled atmospheres (CA) and air were evaluated after longterm storage in terms of sensory attributes and physicochemical parameters, namely colour, firmness, polyphenoloxidase (PPO) activity and concentration of hydroxycinnamic compounds. The CA conditions were all combinations of 2 and 4% (v/v) O2 with 0.5 and 1.5% (v/v) CO2. Storage under CA conditions produced a beneficial effect on ‘Rocha’ pears in maintaining their quality and, consequently, in extending their shelf life and acceptability. Clear differences in sensorial attributes, colour parameters and PPO activity were found between CA- and air-stored pears. The effect provided by the CA conditions persisted throughout the time of exposure to the open air. The 2%O2 concentration produced amore beneficial effect than its 4%counterpart on the sensorial and physical characteristics of the pears.The former concentration of O2 prevented yellowing and allowed regular softening, hence keeping a high flavour quality. No clear effects could be associated with CO2 levels. Empirical models were developed that describe the effects of O2 and CO2 concentrations, as well as time at room temperature on physicochemical parameters pertaining to ‘Rocha’ pears

Infrared spectroscopy and flow analysis for the determination of chemical constituents in food products

Two analytical methods were proposed for the determination of sodium chloride. A flow injection turbidimetric determination, based on the precipitation of silver chloride, was found to be a simple methodology to be implemented for routine analysis with a high sampling frequency, low reagent consumption and waste production in comparison with the reference methodology. On the other hand, the infrared methodology allowed NaCl determination with no reagent consumption. Both methodologies can be implemented for routine chemical analysis determinations in the food industry

Monitoring sodium chloride during cod fish desalting process by flow injection spectrometry and infrared spectroscopy

In order to adapt to the market trends that are moving towards ready-to-use products cod !sh industry is including into their industrial operations as the desalting step. The desalting process is a high cost and time demanding operation. The optimization of the desalting process is of vital importance for the !sh industry in order to assure the homogeneity and predictable concentration of sodium chloride in the !nal hydrated cod !sh product. On the other hand, consumers are more aware about the necessity to bring sodium consumption down to healthy levels to prevent cardiovascular diseases. The application of rapid and simple analytical methodologies that permit the control of the process and ensure food quality is essential in the food industries. This work reports the optimization and application of two analytical methodologies with the objective of monitoring the variation of sodium chloride concentration during cod desalting process. A "ow injection analysis system was developed based on the reaction between chloride and silver nitrate, and the formed precipitate was assessed spectrophotometrically as a turbidity change. A Fourier-mid infrared spectroscopy attenuated total re"ection method was also applied. Different chemical and physical parameters of the "ow injection system were studied and the analytical characteristics of both systems were compared.info:eu-repo/semantics/acceptedVersio