ABSTRACT
Our objective was to elaborate lactose-free Dulce de leche (DL) and evaluate the influence of the hydrolysis of this sugar on the attributes of the products. Fluid milk used was divided into two portions and, in one of them, enzymatic hydrolysis of lactose was carried through. Next, the homogenization of milk was performed at 20 MPa. Four different treatments were studied. The final products were evaluated in relation to their composition and physico-chemical characteristics. The main results show that the homogenized lactose-free DL obtained a higher concentration of free 5-Hydroxymethylfurfural (HMF) (133.77 ± 3.42 µmol l-1). Consequently, browning was more intense due to Maillard Reaction. Texture parameters were higher (1611.00 ± 598.78 g hardness and 19.52 ± 2.46 g gumminess) when compared to the homogenized traditional product (28.45 ± 1.16 µmol l-1 free HMF, 437.17 ± 279.3 g hardness, and 406.20 ± 311.69 g gumminess). Lactose-free products are in high demand by consumers; however, the results of this work highlight the challenges to properly control the browning and the texture parameters of DL.
Subject(s)
Lactose , Milk , Animals , Hydrolysis , Maillard ReactionABSTRACT
The aim of this study was to evaluate the effects of bulk tank milk (BTM), WM, and PWM on the intake, ruminal parameters, blood parameters, health, and performance of dairy calves. Forty-five male crossbred dairy calves (Gyr × Holstein) were used. On their fourth day of age, animals were grouped according to body weight, serum protein levels, and genetic composition. Three treatments were assessed: BTM (n = 15), WM from cows in antibiotic treatment (n = 15), and PWM via high-temperature, short-time pasteurization (72-74 °C for 16 s) (n = 15). During the experimental period (from 4 to 60 d of age), animals were fed 6 L of milk/d, divided into two equal meals. Water and concentrate were provided ad libitum. Daily measurements were made for milk, concentrate, and water intakes, as well as for fecal and respiratory scores. Rumen fluid and blood were sampled weekly. The following parameters were evaluated: volatile fatty acids (VFAs), pH and ammonia-N in rumen fluid, and ß-hydroxybutyrate (BHB) and glucose in blood. Animals were weighed at birth, 4 d of age, and weekly up to 60 d of age. At the end of the experimental period (60 ± 1 d), all animals were euthanized for pulmonary evaluation. The randomized complete design with an interaction between treatment and week was the experimental method of choice for testing the hypothesis of the treatment's effect on all evaluated outcomes. Animals in the BTM treatment had higher milk dry matter intake (DMI), followed by WM and PWM calves. Concentrate DMI was lower for BTM in comparison to WM and PWM calves. However, total DMI showed no significant differences between treatments. The rumen fluid from calves receiving PWM had higher concentrations of acetate and propionate than that of BTM and WM animals. No differences were observed between treatments for blood glucose and BHB concentrations. Health parameters (fecal and respiratory scores) and pneumonia occurrence showed no significant difference between treatments. No differences were observed for average daily gain (ADG) or body growth. Feeding WM and PWM did not show significant negative effects on the intake, ruminal parameters, blood parameters, health, or performance of dairy calves.
ABSTRACT
The beneficial effects of a healthy diet on the quality of life have prompted the food industry to develop low-fat variants, but fat content directly affects the physicochemical and sensory properties of food products. The utilization of high-pressure homogenization (HP) and incorporation of hydrocolloids have been suggested as strategies to improve the physical stability and rheological properties of light cream. Thus, this study aims to analyze the associated effect of high-pressure homogenization (80 MPa) and three different hydrocolloids: microcrystalline cellulose, locust bean gum and xanthan gum, on emulsion stability and rheological properties of ultra-high-temperature (UHT) light cream (ULC) with a 15% w/w fat content. The stability of ULC was determined by the ζ potential of oil droplets and emulsion stability percentage. Rheological characterization was based on flow behavior tests and dynamic oscillatory measurements, which were carried out in a rheometer. Results showed that the high-pressure homogenization process did not influence the emulsion stability of the treatments. Moreover, the hydrocolloids added to systems present weak interactions with milk proteins since all ULC showed macroscopical phase separation. The samples presented the same rheological behavior and were classified as pseudoplastic fluids (n < 1). ULC treated at 80 MPa was significantly (P ≤ 0.05) more consistent than the treatments at 20 MPa. All ULC showed a predominant elastic behavior (G' > Gâ³), and a remarkable increase in both G' and Gâ³ at 80 MPa. The results presented in this study highlight the potential of HP for altering some rheological characteristics of UHT light cream, for example, to increase its consistency. These results are important for the dairy industry and ingredient suppliers, in the standardization of UHT light cream and/or to develop low-fat products.
Subject(s)
Colloids/administration & dosage , Dairy Products , Dietary Fats/analysis , Food Handling/methods , Hot Temperature , Milk/chemistry , Animals , Cellulose , Chemical Phenomena , Diet, Fat-Restricted , Emulsions , Galactans , Mannans , Plant Gums , Polysaccharides, Bacterial , Pressure , RheologyABSTRACT
Using membrane filtration it is possible to selectively concentrate proteins and, in the case of microfiltration, concentrate casein micelles. During filtration, water is often added and this practice, called diafiltration, causes further release of permeable components and maintains filtration efficiency. Filtration causes changes in composition of the protein as well as the soluble phase, including soluble calcium, which is a critical factor controlling the gelation properties of the casein micelles in milk. It was hypothesized that concentrates obtained using membrane filtration with or without diafiltration would have different gelation behavior. To test this hypothesis, two concentrates of similar casein micelle volume fraction were prepared, using spiral wound polymeric microfiltration membranes with a 800 kDa molecular weight cutoff, with or without diafiltration. The concentrates showed a gelation behavior comparable to that of skim milk, with a similar gelation time and with a higher firmness, due to the higher number of protein linkages in the network. In contrast, the hydrolysis of κ-casein by chymosin and casein aggregation were inhibited in diafiltered casein micelle suspensions. When the concentrates were recombined with the original skim milk to a final concentration of 5% protein, which re-established a similar soluble phase composition, differences in gelation behavior were no longer observed: both treatments showed similar gelation time and gel firmness. These results confirmed that membrane filtration can result in concentrates with different functionality, and that ionic environmental conditions are critical to the aggregation behavior of casein micelles. This is of particular significance in industrial settings where these fractions are used as a way to standardize proteins in cheese making.
Subject(s)
Caseins/chemistry , Caseins/isolation & purification , Filtration/methods , Gels/chemistry , Micelles , Water/chemistry , Animals , Calcium/analysis , Calcium/chemistry , Caseins/metabolism , Chymosin/metabolism , Milk/chemistry , Milk Proteins/analysis , Milk Proteins/chemistry , Milk Proteins/metabolism , Phosphates/analysis , Phosphates/chemistry , Rheology , SolubilityABSTRACT
The work described in this Research Communication concerns the production of Dulce de leche (DL), that is a traditional product from South America obtained by concentration. Maillard reaction (MR) products are mainly responsible for the formation of color and flavor in this product. Lactose-hydrolyzed products have been developed to supply consumer demand, but this hydrolysis may affect the flavor, color, taste, texture and even some nutritional aspects of the product. We studied the influence of different levels of lactose-hydrolysis, sucrose addition and initial pH on the development of MR, appraised by the determination of 5-hydroxymethylfurfural (HMF). A process simulator with multi-monitoring system was used to produce 15 DL. Box-Behnken 33 experimental design was applied for the three factors: pH, lactose-hydrolysis level and sucrose concentration. Lipids, protein, ashes, carbohydrates, water activity, dissolved solids, colorimetric analysis and HMF (free and total) are among the physicochemical attributes and MR indicators analyzed in this work. The products showed significant differences in composition but all the values were in agreement with the literature. Moreover, higher levels of lactose hydrolysis and higher pH presented a direct relation with the development of MR, observed by an increase in coloration (lower luminosity) and more formation of HMF, both free and total. The present study expands the knowledge about DL spread made of lactose-hydrolyzed milk, allowing the food industries to produce a lactose free DL with nutritional and sensory characteristics closer to the traditional product.
Subject(s)
Furaldehyde/analogs & derivatives , Lactose/chemistry , Milk/chemistry , Animals , Chemical Phenomena , Color , Food Handling/methods , Furaldehyde/chemistry , Hydrogen-Ion Concentration , Hydrolysis , Maillard Reaction , South America , Sucrose/analysis , Sucrose/chemistry , TasteABSTRACT
The objective of this work was to evaluate the impact of changes during membrane filtration on the heat stability of milk protein concentrates. Dairy protein concentrates have been widely employed in high protein drinks formulations and their stability to heat treatment is critical to ensure quality of the final product. Pasteurized milk was concentrated three-fold by membrane filtration, and the ionic composition was modified by addition of water or permeate from filtration (diafiltration). Diafiltration with water did not affect the apparent diameter of the casein micelles, but had a positive effect on heat coagulation time (HCT), which was significantly longer (50 min), compared to the non diafiltered concentrates (about 30 min). UHT treatments increased the particle size of the casein micelles, as well as the turbidity of retentates. Differences between samples with and without diafiltration were confirmed throughout further analysis of the protein composition of the unsedimentable fraction, highlighting the importance of soluble protein composition on the processing functionality of milk concentrates.
Subject(s)
Filtration/veterinary , Hot Temperature , Milk Proteins/chemistry , Milk Proteins/isolation & purification , Animals , Calcium/analysis , Caseins/chemistry , Chemical Phenomena , Drug Stability , Filtration/methods , Micelles , Milk/chemistry , Particle Size , Pasteurization , Phosphates/analysis , Ultrafiltration/veterinaryABSTRACT
Omega-3 and omega-6 fatty acids are structurally, functionally and metabolically different. Such fatty acids play opposite biological functions by their intervention in numerous physiological processes such as blood coagulation and inflammatory and immunological responses, thus affecting the development of chronic diseases. Such effects are in part due to the differences in the concentration of omega-3 and omega-6 fatty acids in the diet, i.e. a large intake of omega 6 in contrast to a small one for the omega 3. This paper analyses several issues with respect to the biological role of these fatty acids in the development of chronic diseases, as well as their characteristics in the context of food intake
Los ácidos grasos omega-3 y omega-6 además de ser estructuralmente diferentes, se distinguen también funcional y metabolitamente. Es os ácidos grasos realizan funciones biológicas opuestas, participan en numerosos processos fisiológicos, tales como: coagulación de la sangrey en las respuestas inflamatoria e inmunológica, influyendo de esta forma el proceso de aparecimiento de las enfermedades crónicas no transmisibles. Esa influencia se debe, en parte,a la concentración desproporcionada de ácidos grasos omega-3 y omega-6 que la dieta contiene. Una elevada concentración de ácidos grasos omega-6 frente a una escasez de omega-3. La finalidad de este estudio es analizar el papel biológico de eso ácidos grasos en el proceso de aparecimiento de enfermedades crónicas no trasmisibles, así como presentar sus características en el contexto de la ingestión alimentar.
Os ácidos graxos das séries ômega 3 e 6 são estruturalmente diferentes, assim, como o são funcional e metabolicamente. Tais ácidos graxos desempenham funções biológicas opostas, intervindo em numerosos processos fisiológicos tais como, a coagulação do sangue e as respostas inflamatórias e imunológicas, influenciando assim no processo de desenvolvimento de doenças crônicas não transmissíveis. Tal influência é devida, em parte, à desproporção da concentração dos ácidos graxos ômega 3 e ômega 6, existente na dieta, ou seja, uma grande concentração de ácidos graxos ômega 6, frente à escassez de ômega 3. Assim, o presente estudo se propôs a analisar as questões referentes ao papel biológico de tais ácidos graxos no processo de desenvolvimento de doenças crônicas não transmissíveis, bem como apresentar suas características no contexto da ingestão dietética
