New Methodologies for Kinetic Study of 5-(Hydroxymethyl)-Furfural Formation and Reactive Lysine Blockage in Heat-Treated Milk and Model Systems

Abstract

New analytical techniques were used to study the kinetic behavior of 5-(hydroxmethyl) furfural (HMF) and blockage of available lysine in milk and model systems. Both determination of HMF by the chromatographic method and estimation of available lysine by the ortho-phthaldialdehyde (OPA) method at sterilization temperatures proved valid. Activation energies for the lysine loss reaction were 91.14, 112.41 and 66.67 kJ·mol−1 in the model systems and the milk respectively in fluorimetric determination with OPA. Activation energy for HMF determination ranged from 118.5 to 93.04 kJ·mol−1

Fluorometric determination of chemically available lysine: Adaptation, validation and application to different milk products

“…To adapt the method to our samples and to improve quantification, two modifications have been made in the method used by Morales et al [19] to estimate in a relative measure the chemically available lysine contents of dairy products, based in turn on the reaction between free (e-amino acid groups and OPA studied by Goodno et al [18]. The modifications firstly comprise a reduction in the ratio between the amounts of liquid or reconstituted sample and the sodium dodecyl sulfate (SDS) used to obtain a clear solution to carry out the assay, and secondly the use of bovine casein instead of quinine sulfate as standard for the quantification.…”

“…The same reaction was used by Vigo et al [15] to determine available lysine in milk products by spectrophotometry, and by Morales et al [19] to set up a fluorometric method for estimating available lysine in liquid milk in a non-quantitative determination. The use of OPA offers the following advantages with respect to other methods: in contrast to the indirect FDNB method [23], it does not require either hydrolysis or amino acid analysis of the sample; unlike spectrophotometric procedures using FDNB [13], TNBS [24] does not require either heating or solvent extraction that can release lysine from modified forms.…”

“…Different methods (spectrophotometric [13][14][15], chromatographic [16,17], fluorometric [18,19]) have been proposed for the determination of available lysine content. Different chemical methods (guanidation, reduction with sodium borhydride, fluorodinitrobenzene direct method and indirect difference method, dye-binding lysine) have been compared [8,20,21], the conclusion being that the determination of furosine and the Carpenter method (1960) are the most appropriate for estimating reactive lysine in milk.…”

New strategy to improve acrylic/casein compatibilization in waterborne hybrid nanoparticles

“…10,11 Zeta potential was measured with a Malvern Nano ZS equipment. The 1 H NMR spectra were obtained with a 300 MHz Bruker spectrometer.…”

Exploring the potential of an Andean fruit : an interdisciplinary study on the cape gooseberry (Physalis peruviana L.) value chain

“…The parameter estimation results were (± 95% confidence intervals): HMF formation has been described as a zero-order reaction for milk and apple cider [229,231] and as a first-order reaction for honey and apple juice [232,230] …”