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1.
J Sci Food Agric ; 100(3): 1132-1141, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31680255

RESUMO

BACKGROUND: Production and marketing of cereal grains are some of the main activities in developing countries to ensure food security. However, the food gap is complicated further by high postharvest loss of grains during storage. This study aimed to compare low-cost modified-atmosphere hermetic storage structures with traditional practice to minimize quantitative and qualitative losses of grains during storage. The study was conducted in two phases: in the first phase, seven hermetic storage structures with or without smoke infusion were compared, and one selected structure was further validated at scaled-up capacity in the second phase. RESULTS: Grains stored in PVC bag-supported structures (with or without smoke infusion) resulted in low live weevil population, low percentage of damaged grains and reduced weight loss with better retention of crude protein and fat contents. Results from validation study also demonstrated that maize and sorghum stored in improved storage structures experienced, respectively, 9.8% and 10.4% weevil damage as compared with 47.3% and 42.3% when stored in traditional storage structures. The same was true in terms of crude protein and fat contents. CONCLUSIONS: The study demonstrated that storage structures supported with PVC bags are efficient and low-cost structures for reducing storage-related losses and supporting food security efforts as compared to traditional methods. Furthermore, the bags can be made locally and with various storage capacities to store either shelled or unshelled products. © 2019 Society of Chemical Industry.


Assuntos
Armazenamento de Alimentos/métodos , Sorghum/química , Zea mays/química , Animais , Atmosfera , Armazenamento de Alimentos/economia , Armazenamento de Alimentos/instrumentação , Sorghum/parasitologia , Gorgulhos/crescimento & desenvolvimento , Gorgulhos/fisiologia , Zea mays/parasitologia , Cimento de Óxido de Zinco e Eugenol/análise
2.
Food Chem ; 302: 125327, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31404870

RESUMO

The effect of tomato lycopene-rich extract (TLE) addition on shelf-life of linseed oil was evaluated. Linseed oil was extracted by cold pressing and TLE by supercritical CO2. Linseed oils with and without TLE addition were characterized for moisture, color, refractive index, fatty acid composition and antioxidants. Adding TLE to 80 mg lycopene/kg oil improved linseed oil stability, showing the same induction time at 110 °C (by Rancimat) of control linseed oil with 200 mg/kg butylhydroxytoluene. The increase of free fatty acid, peroxide value, p-anisidine value, K232 and K268 at 40, 50, and 60 °C until 90 days followed first-order kinetics. Rancidity rate augmented with temperature. TLE addition slowed oil degradation without changing the mechanism since the Arrhenius lines were parallel. Mean Ea were respectively 38.2, 24.7, 38.0, 38.2, 41.5 kJ/mol. TLE addition increased linseed oil shelf-life by 31% (Rancimat) and by 42% (stability kinetics during storage).


Assuntos
Armazenamento de Alimentos/métodos , Óleo de Semente do Linho/química , Licopeno/química , Lycopersicon esculentum/química , Extratos Vegetais/química , Compostos de Anilina/análise , Antioxidantes/análise , Antioxidantes/química , Hidroxitolueno Butilado/química , Cor , Ácidos Graxos/análise , Hidrólise , Cinética , Oxirredução , Peróxidos/análise
3.
J Sci Food Agric ; 100(2): 775-784, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31605378

RESUMO

BACKGROUND: Bottle storage can affect color, aroma and phenolic composition of white wine. Very little information is reported about the bottle evolution during storage of white wines without added sulfites and/or using other antioxidants. This work is aimed at studying the evolution of the main enological parameters, phenolic and volatile profiles of a white wine without added sulfites, during 15 months of storage in bottle at different light and temperature conditions, compared with a control stored with sulfur dioxide. Dark storage at 12 °C (D12-S, D12-NS) and 30 °C (D30-S, D30-NS) were compared to investigate the temperature effect, meanwhile uncontrolled temperature and light condition (UTL-S, UTL-NS) simulated improper storage conditions. RESULTS: Volatile acidity, absorbance at 420 nm and total phenols were higher in UTL-NS and D30-NS wines. The trans forms of hydroxycinnamic esters decreased, whereas, the cis forms, as well as caffeic acid derivatives, significantly increased in samples without added sulfites. The storage without sulfites also accelerated the hydrolysis of acetate esters. However, it did not affect most of the ethyl esters whose content remained almost the same between sulfite added (S) and no sulfite added (NS) wines. CONCLUSION: The presence of sulfites in the bottle helped to preserve the volatile compounds of young wines; however, even more important seemed to be the optimal storage (dark and low temperature), as unsuitable conditions favored aroma degradation of bottled wine, regardless of sulfite protective action. © 2019 Society of Chemical Industry.


Assuntos
Armazenamento de Alimentos/métodos , Fenóis/análise , Sulfitos/análise , Compostos Orgânicos Voláteis/análise , Vinho/análise , Cor , Humanos , Hidrólise , Espectrometria de Massas , Odorantes/análise , Dióxido de Enxofre/análise , Paladar , Temperatura Ambiente
4.
Int J Food Microbiol ; 312: 108375, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31669767

RESUMO

Recently, oxo-biodegradable polymers have attracted much attention due to taking less time to break down after disposal in comparison to ordinary polymers. Polyvinyl alcohol/gelatin (PVA/G) nanocomposite films, containing ZnO, TiO2 or ZnO/TiO2 nanoparticles supported on 4A zeolite (4A z), are novel active packaging that can control the release of antimicrobial compounds. The present study assessed the efficacy of PVA/G nanocomposite films with 1.5% (w/w) ZnO/4A z (treatment 1), 1.5% (w/w) TiO2/4A z (treatment 2), or 1% (w/w) ZnO, TiO2/4A z (treatment 3) in controlling the microbial load and maintaining the sensory qualities of white shrimp during storage at 4 ±â€¯1 °C. Firstly, the optimum concentration of each material for addition to the film was determined by micro-dilution and disc diffusion. Secondly, the specimens were checked for total viable count (TVC), as well as the counts of each of Pseudomonas spp., Enterobacteriaceae, Shewanella putrefaciens, inoculated Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli O157:H7. According to the results, the PVA/G nanocomposite films containing treatments 1-3 significantly decreased the number of bacteria in the treatment group in comparison to the control group (P < .05). The results of the antimicrobial activity of the three treatments by using the disc diffusion method revealed that the inhibition zone varied from 8.11 ±â€¯0.02 to 12.63 ±â€¯0.04 mm. Also it should be noted that, the finding of micro-dilution test varied from 1 ±â€¯0.01 to 3 ±â€¯0.01. The ZnO, TiO2/4A z nanocomposite had a significantly greater antimicrobial impact against Gram-negative bacteria compared to Gram-positive bacteria (P < .05). Finally, the microbiological and sensory investigation of the efficacy of the PVA/G nanocomposite films as active packaging materials revealed a considerable improvement in shrimp shelf life (12 days) in comparison to the control (6 days). Therefore, these nanocomposite films can be used as novel active packaging in the maintenance of the microbial load and sensory qualities of shrimp.


Assuntos
Antibacterianos/farmacologia , Embalagem de Alimentos/métodos , Armazenamento de Alimentos/métodos , Penaeidae/microbiologia , Titânio/farmacologia , Zeolitas/farmacologia , Óxido de Zinco/farmacologia , Animais , Carga Bacteriana/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Gelatina/farmacologia , Listeria monocytogenes/efeitos dos fármacos , Nanocompostos , Nanopartículas , Álcool de Polivinil/farmacologia , Refrigeração , Staphylococcus aureus/efeitos dos fármacos
5.
Food Chem ; 305: 125454, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31505413

RESUMO

The effects of the (-)-Epigallocatechin gallate (EGCG)-gelatin biofilm treatment (EGT) on microbial composition and quality of tilapia fillets stored at low temperatures were evaluated. The changes in mechanical properties, microbial reproduction, as well as lipid and protein oxidation during fillets storage were determined. The results showed that EGT reduced the microbial count and the relative abundance of the fillets. And EGT delayed the rate of lipid oxidation and protein denaturation in fillets. Compared with the control group, EGT samples had lower K values (74% on 18 d) and biogenic amines (39 mg/kg for putrescine and 50 mg/kg for cadaverine on 21 d). According to sensory evaluation, the shelf life of tilapia fillets was extended by 6 d in the EGT group. Therefore, EGT improved the quality of cryopreserved tilapia fillets and could be considered as a potential method for fish fillet preservation.


Assuntos
Materiais Biomiméticos/química , Catequina/análogos & derivados , Armazenamento de Alimentos/métodos , Gelatina/química , Alimentos Marinhos/análise , Aeromonas/efeitos dos fármacos , Animais , Aminas Biogênicas/análise , Materiais Biomiméticos/farmacologia , Catequina/química , Peroxidação de Lipídeos/efeitos dos fármacos , Desnaturação Proteica/efeitos dos fármacos , Proteínas/química , Pseudomonas/efeitos dos fármacos , Alimentos Marinhos/microbiologia , Paladar/efeitos dos fármacos , Temperatura Ambiente
6.
Int J Food Microbiol ; 313: 108377, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31670166

RESUMO

The ability of three Penicillium expansum isolates to produce patulin was first evaluated in YES medium after incubation at 25 °C to select a high patulin producer. Then, a spore suspension of the selected P. expansum 3.78 strain was inoculated onto the surface of Golden delicious apples and incubated at 8 or 20 °C until the mold lesion reached a diameter of 1, 2 or 3 cm. For each lesion size, patulin was quantified from apple samples cut into 1 cm depthwise fractions and widthwise sized cylinders. Maximum patulin concentration, about 80,000 ng/g apple, was obtained at 8 °C for the center and surface sample of the 3 cm diameter lesion. Patulin was systematically found at the highest concentration in the lesions, but still quantified up to one centimeter next to the lesion. Patulin concentrations were not significantly different between the 8 and 20 °C incubation temperature, except for the 3 cm large lesions. Based on these findings, and for lesions less than or equal to 3 cm in diameter, we recommend to consumers to cut off at least 1 cm around and below the mold spot to limit patulin exposure. Apples should also be stored at cool temperatures, below 8 °C, to delay lesion development.


Assuntos
Armazenamento de Alimentos/métodos , Frutas/química , Malus/microbiologia , Patulina/análise , Penicillium/metabolismo , Armazenamento de Alimentos/instrumentação , Frutas/microbiologia , Malus/química , Patulina/biossíntese , Penicillium/crescimento & desenvolvimento , Temperatura Ambiente
7.
J Sci Food Agric ; 100(2): 551-559, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31587285

RESUMO

BACKGROUND: Phosphorylation is one of the most important post-translational modifications. Currently, many postmortem protein phosphorylation studies in muscle have been related to meat quality such as tenderness and color stability. However, the effects of various storage temperatures (25, 15, 4 and -1.5 °C) on the phosphorylation level of protein are poorly understood. Changes in the protein phosphorylation levels in postmortem ovine muscle at various storage temperatures were determined in this study. RESULTS: The obtained data showed that pH decline rate was significantly inhibited at -1.5 °C from 12 h to 7 days postmortem (P < 0.05). The ATP consumption rate was higher at 25 °C than that at other three temperatures (P < 0.05). Analysis of the temperature, pH and ATP content revealed that the ATP content was related to the phosphorylation levels of individual protein bands. Phosphorylated myofibrillar and sarcoplasmic proteins, such as myosin binding protein C, troponin T3, myosin light chain 1, glucose-6-phosphate isomerase and pyruvate kinase, were mainly involved in glycolysis and muscle contraction. CONCLUSION: The global and specific protein phosphorylation levels can be influenced by the postmortem storage temperature of muscle. Phosphorylation of proteins was correlated with glycolysis and muscle contraction. Certain phosphorylated proteins, such as heat shock proteins, require further study to clarify their effects on meat traits. © 2019 Society of Chemical Industry.


Assuntos
Armazenamento de Alimentos/métodos , Carne/análise , Proteínas Musculares/química , Músculo Esquelético/química , Animais , Armazenamento de Alimentos/instrumentação , Glicólise , Fosforilação , Mudanças Depois da Morte , Ovinos , Temperatura Ambiente
8.
J Food Sci ; 84(11): 3147-3155, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31599978

RESUMO

Oxidative stability of hempseed and soybean oils, was evaluated after heating at 180 °C, followed by a subsequent 14-day storage at 38 °C. Natural plant extracts (Rosemary, Sage, and Thyme) were added to oils, to evaluate the carry-over stabilizing potential. Heated oils exhibited a relatively faster (P < 0.05) onset of lipid oxidation, as depicted by the analysis of the peroxides and aldehydes formed during the lipid oxidation process, with hempseed oil being more susceptible to lipid oxidation than soybean oil. There were notable losses in ω-3 PUFA and ω-6-GLA during storage of heat treated hempseed oil (P < 0.05). Moreover, peroxide values measured from hempseed oil remained low after high-temperature heating but progressed at a relatively greater rate than that observed in soybean during storage (P < 0.05). The addition of different plant extracts to oils did not prevent oxidation due to heating, but effectively inhibited the generation of hydroperoxides during subsequent storage (P < 0.05). This stabilizing effect was attributed to retention of tocopherols, in particular, γ-tocopherol. PRACTICAL APPLICATION: This research demonstrates the use of plant extracts like rosemary, sage and thyme, for improving the shelf-life and nutritional stability of hempseed and soybean oil. We demonstrate the deterioration of fatty acid profiles and vitamin E levels in the oil on heating and subsequent storage, and show the efficacy of using plant extracts in slowing down these deteriorations. This research will be applicable in food industries using or producing oils for use in food during cooking, and also as dressing on already processed food products.


Assuntos
Cannabis/química , Ácidos Graxos Ômega-3/análise , Manipulação de Alimentos/métodos , Extratos Vegetais/farmacologia , Óleo de Soja/química , Vitamina E/análise , Ácidos Graxos/análise , Armazenamento de Alimentos/métodos , Temperatura Alta , Peróxido de Hidrogênio/análise , Peroxidação de Lipídeos/efeitos dos fármacos , Óleos Vegetais/química , Rosmarinus/química , Salvia officinalis/química , Sementes/química , Thymus (Planta)/química
9.
J Food Sci ; 84(11): 3109-3116, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31604372

RESUMO

In this study, 1 H NMR and multivariate data analysis were used to investigate the effect of coating incorporated with black pepper essential oil (CIBPEO) on the taste of Jinhua ham after 4 months of storage; four treatments of control check (CK), base formula coating (BC), BC + 0.05% BPEO, and BC + 0.1% BPEO were used for the coating of hams. Results showed that the metabonome was dominated by 23 metabolites, including amino acids, sugar, organic acids, alkaloids, nucleic aides and their derivatives, and others. BPEO decreased the intensity of sourness, sweetness, bitterness, aftertaste, and the relative nonvolatile taste metabolites compared to CK and BC; the decrease of intensity was not dependent on the BPEO contents. These findings demonstrated that CIBPEO could give a new taste balance to Jinhua ham and be beneficial to a group of people with a particular sensory preference, who are sensitive to undesirable sourness and bitterness, and prefer a light overall taste. PRACTICAL APPLICATION: The coating incorporated with black pepper essential oil during storage could give a new taste balance to Jinhua ham and be beneficial to a group of people with a particular sensory preference, who are sensitive to undesirable sourness and bitterness, and prefer a light overall taste.


Assuntos
Armazenamento de Alimentos/métodos , Óleos Voláteis/administração & dosagem , Piper nigrum/química , Paladar , Aminoácidos , Humanos , Espectroscopia de Ressonância Magnética , Análise Multivariada
10.
Meat Sci ; 158: 107878, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31401371

RESUMO

We investigated the fatty acid (FA) composition, oxidative biomarkers and quality traits of chilled beef. Specifically, striploin portions were held in vacuo and chilled (~ 1.5 °C) for up to 12 weeks, and analysed dependent on their assigned chilled storage period (0, 2, 5, 8, 10 and 12 weeks). There were no practical effects observed on beef FA composition as a result of chilled storage - including several polyunsaturated FA (PUFA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Intramuscular fat content was found to have a covariate effect, but only for saturated FA and monounsaturated FA. Vitamin E and thiobarbituric acid reactive substances were unchanged. Furthermore, improvements to shear force and particle size were evident at 2 weeks and thereafter, no further variation was evident. These findings suggest that beef produced to be healthier based on the EPA, DHA and PUFA content will remain so, for up to 12 weeks. Likewise, beef quality will be preserved across this same period.


Assuntos
Ácidos Graxos/análise , Carne Vermelha/normas , Refrigeração , Animais , Austrália , Biomarcadores , Bovinos , Ácidos Docosa-Hexaenoicos/análise , Ácido Eicosapentaenoico/análogos & derivados , Armazenamento de Alimentos/métodos , Oxirredução , Carne Vermelha/análise , Resistência ao Cisalhamento , Vácuo
11.
Food Chem ; 301: 125311, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31398670

RESUMO

We assessed the effects of postharvest exogenous melatonin (50,100 and 150 µmol L-1) on the senescence and quality of sweet cherries during storage at 0 ±â€¯0.5 °C. Melatonin treatment decreased decay incidence, respiration rate, and weight loss. It delayed the degradation of firmness, lightness, saturation, hue angle, titratable acidity, and total soluble solids content, thus maintaining better fruit quality. Melatonin treatment inhibited increases in O2-, H2O2, malondialdehyde content, and relative membrane permeability, while maintaining higher endogenous melatonin levels and increasing superoxide dismutase and catalase activity. Additionally, melatonin treatment enhanced the activity of antioxidant enzymes, increased the levels of ascorbic acid, and reduced glutathione levels, which are related to the ascorbate-glutathione cycle, as well as increasing the AsA:DHA and GSH:GSSG ratios. Delayed senescence in sweet cherries after exogenous melatonin treatment may be associated with high endogenous melatonin levels and increased antioxidant activity and content.


Assuntos
Armazenamento de Alimentos/métodos , Frutas/efeitos dos fármacos , Melatonina/farmacologia , Prunus avium/efeitos dos fármacos , Antioxidantes/metabolismo , Ácido Ascórbico/metabolismo , Qualidade dos Alimentos , Frutas/fisiologia , Glutationa/metabolismo , Malondialdeído/metabolismo , Melatonina/metabolismo , Oxirredução , Prunus avium/fisiologia , Superóxido Dismutase/metabolismo
12.
Meat Sci ; 158: 107856, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31430644

RESUMO

Citrate synthase belongs between mitochondrial enzymes which are released from the meat tissue after cell membrane damage caused by ice crystal formation. The presence of this enzyme can indicate a previous freezing process. In this study, we determined citrate synthase activity for chilled and frozen/thawed meats (chicken, pork, beef, and salmon). As an additional factor, we examined a potential connection between microbial spoilage and increased enzyme activity. UV spectrophotometry was used for the evaluation of the citrate synthase activity. The effect of microbial spoilage on the enzyme activity was established through microbial analysis, which was carried out for two weeks for chilled and five months for frozen/thawed meats. The citrate synthase activity in the frozen/thawed samples was significantly higher than in the chilled samples. Dependence of microbial contamination and the increased activity of the citrate synthase was not observed. Our results suggest that there could be designed specific limits of citrate synthase activity for the resolution of chilled and frozen/thawed meats.


Assuntos
Citrato (si)-Sintase/análise , Congelamento , Carne/análise , Animais , Bovinos , Galinhas , Armazenamento de Alimentos/métodos , Carne/microbiologia , Salmão , Espectrofotometria Ultravioleta , Suínos
13.
J Dairy Res ; 86(3): 361-367, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31423963

RESUMO

This research paper addresses the hypothesis that the fortification of goat milk base with whey protein concentrate (WPC) could affect both the textural and the biofunctional properties of set-style yoghurt. The effect of fortification of goat milk base with two different WPCs on thermophilic bacteria counts, proteolysis, physical and biofunctional properties of set-style yoghurts was studied at specific sampling points throughout a 4-week storage period. Fortification and storage did not influence thermophilic counts. Physical properties were affected significantly (P < 0.05) by the composition of the protein and the mineral fraction of the WPC but not by the storage. ACE-inhibitory activity was moderate in accordance to low lactobacilli counts and lack of proteolysis. DPPH-radical scavenging activity, Fe2+-chelating activity and superoxide scavenging activity were high. At 28 d an anti-inflammatory effect was observed, which was not affected by WPC addition.


Assuntos
Alimentos Fortificados/análise , Cabras , Leite/química , Proteínas do Soro do Leite/análise , Iogurte/análise , Inibidores da Enzima Conversora de Angiotensina/análise , Animais , Carga Bacteriana , Fenômenos Químicos , Fermentação , Armazenamento de Alimentos/métodos , Depuradores de Radicais Livres/análise , Quelantes de Ferro/análise , Lactobacillus/crescimento & desenvolvimento , Lactobacillus/isolamento & purificação , Iogurte/microbiologia
14.
Ultrason Sonochem ; 59: 104712, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31421620

RESUMO

In this study, the effect of sweep frequency ultrasound (SFUS), sodium hypochlorite (NaOCl) and their combinations (SFUS + NaOCl) in reducing and inhibiting natural microbiota as well as preserving quality of fresh-cut Chinese cabbage during storage (4 °C and 25 °C) for up to 7 days was investigated. In effect, 40 kHz sweep frequency ultrasound in combination with 100 mg/L sodium hypochlorite resulted in maximum reduction and inhibition of mesophilic counts, yeast and molds and minimum chlorophyll depletion, weight loss and electrolyte leakage. However, colour and textural characteristics deteriorated. The combined treatment suppressed the activities of polyphenol oxidase and peroxidase and manifested its preservative effect after Fourier Transform near-infrared spectroscopy analysis. Synergistic reductions were recorded in most of the combined treatments though largely <1.0 log CFU/g. Specifically, the combined treatment significantly (P < 0.05) reduced mesophilic counts by an added 2.7 log CFU/g, yeasts and molds by an added 2.0 log CFU/g when compared to the individual treatments. During storage at 4 and 25 °C, washing with SFUS + NaOCl produced Chinese cabbage with lower microbial counts, in comparison with the individual treatments. However, post-treatment storage could not entirely inhibit microbial survival as populations increased during storage even at refrigeration temperature of 4 °C. The results demonstrate that ultrasound and sodium hypochlorite are promising hurdle alternatives for the reduction and inhibition of microorganisms, as well as prolonging the shelf life and retaining the quality characteristics of Chinese cabbage.


Assuntos
Brassica/microbiologia , Qualidade dos Alimentos , Armazenamento de Alimentos/métodos , Microbiota , Ondas Ultrassônicas , Brassica/química , Brassica/efeitos dos fármacos , Clorofila/análise , Cor , Eletrólitos/análise , Viabilidade Microbiana/efeitos dos fármacos , Microbiota/efeitos dos fármacos , Cloreto de Sódio/farmacologia
15.
Food Chem ; 300: 125219, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31351259

RESUMO

Although storage temperature is important for partial coalescence, the literature is scant on exploring the partial coalescence behavior between refrigerated and room temperature storage. In this study, comparison of the partial coalescence behavior between 4 and 20 °C was investigated towards corresponding oil-in-water emulsions, and subsequently towards the ultimate properties of the aerated colloidal system. As expected, compared to the value of Avrami constant (K) at 20 °C, the value of palm kernel stearin (PKS85) and mixtures of PKS85 and glycerol monostearate (PKS85-GMS) obtained at 4 °C increased by 22 and 14 times, respectively. PKS85 and PKS85-GMS displayed the needlelike appearance (N-type crystal) with a little layer crystal (L-type crystal) at 4 °C and spherical shape formed by L-type crystal along with granular crystal at 20 °C. Interestingly, several unstable air bubbles with irregularly-shape were observed in the aerated emulsions at 20 °C, while these emulsions at 4 °C displayed numerous rounded and uniform air bubbles with glossy surface. This was attributed to the sufficient stiff needle crystals at 4 °C, facilitating the coalescence of fat globules via liquid fat bridges, further forming a rigid crystal-based network and trapping the air bubbles. Therefore, our findings gained an insight into the partial coalescence behavior in emulsion, providing theoretical support for designing and optimizing the production process of foam structure products.


Assuntos
Emulsões/química , Armazenamento de Alimentos/métodos , Ar , Cristalização , Óleo de Palmeira/química , Ácidos Esteáricos/química , Temperatura Ambiente , Água/química
16.
Food Chem ; 300: 125242, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31352285

RESUMO

New antioxidant polyamide was prepared by total immersion in active extract for 48 h. Its antioxidant performance was tested using DPPH (IC50 = 270 ±â€¯21 µg/g) and ORAC (1.52 µmol Trolox/g). In vivo study was done using fresh minced meat stored at 4 °C and analysed after 0, 6, 13, 19, 23 days. After 23 days metmyoglobin (MetMbBK = 31.3 ±â€¯2.9% and MetMbAOX = 25.9 ±â€¯0.8%), CIE L*a*b* (a*BK = 15.0 ±â€¯0.4 and a*AOX = 16.6 ±â€¯0.3) and TBARS (MDABK = 0.0060 ±â€¯0.0003 µg/g and MDAAOX = 0.0044 ±â€¯0.0002 µg/g) showed an improvement of meat shelf life. The results showed that this active film protected meat during 23 days. Migration study to food simulants was done by UPLC®-QqQ-MS and UPLC®-ESI-Q-TOF-MSE. A decrease of oligomers migration (for caprolactam n = 3: BK = 0.050 ±â€¯0.004 mg/Kg; AOX = 0.019 ±â€¯0.001 mg/Kg) was found. INDUSTRIAL RELEVANCE: Nowadays, food industry is focused on improving shelf life of products by controlling its lipid oxidation using natural antioxidants. The obtained results let us design a new active packaging based on natural antioxidants for extending the shelf life of fresh minced meat at industrial scale.


Assuntos
Antioxidantes/química , Embalagem de Alimentos/métodos , Carne , Nylons/química , Chá/química , Animais , Antioxidantes/farmacologia , Cromatografia Líquida de Alta Pressão , Conservação de Alimentos/métodos , Armazenamento de Alimentos/métodos , Metabolismo dos Lipídeos , Carne/análise , Metamioglobina/análise , Nylons/farmacologia , Oxirredução , Espectrometria de Massas por Ionização por Electrospray , Substâncias Reativas com Ácido Tiobarbitúrico/análise
17.
Food Chem ; 300: 125194, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31325749

RESUMO

The effects of near freezing temperature (NFT) storage at -1.9 °C on cell wall degradation of 'Shushanggan' apricot was studied comparing to 0 °C and 5 °C storage. Our results indicated that NFT storage strongly inhibited the solubilization of Na2CO3-soluble pectin and cellulose, by the suppression of cell wall modifying enzymes (polygalacturonase, ß-Galactosidase, pectin methyl esterase and cellulase) and related genes expressions. The loss of side chains was the main modification in CDTA (Cyclohexane-diamine-tetraacetic Acid)-soluble pectin during storage and made the main contribution to the softening of apricot, while the loss of side chain was suppressed by NFT storage. Microscopic observation showed that NFT storage delayed the degradation of pectin fraction and protected cell wall structure from loosing. This study proves that NFT storage is an effective technology to suppress the cell wall polysaccharides degradation and ultrastructure modification of apricot.


Assuntos
Parede Celular/ultraestrutura , Armazenamento de Alimentos/métodos , Polissacarídeos/química , Prunus armeniaca/química , Hidrolases de Éster Carboxílico/química , Hidrolases de Éster Carboxílico/metabolismo , Parede Celular/química , Parede Celular/metabolismo , Celulose/química , Temperatura Baixa , Congelamento , Frutas/química , Frutas/citologia , Frutas/ultraestrutura , Pectinas/química , Células Vegetais/química , Células Vegetais/ultraestrutura , Poligalacturonase/química , Poligalacturonase/metabolismo , Polissacarídeos/metabolismo , Prunus armeniaca/citologia , Solubilidade , beta-Galactosidase/química , beta-Galactosidase/metabolismo
18.
Meat Sci ; 158: 107880, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31326124

RESUMO

The aim of this study was to investigate the permeability properties of synthetic polymeric materials and their influence on the quality of packed chilled pork. Barrier properties of biaxially oriented polypropylene (BOPP) coated with acrylic/polyvinylidene chloride (BOPPAcPVDC) and biaxially oriented coextruded polypropylene (BOPPcoex), were tested on three gases: oxygen, carbon dioxide and nitrogen at different temperatures: 4 °C, 20 °C, 40 °C and 60 °C. Coefficients of permeability, diffusion and solubility were determined. The quality parameters of vacuum packed fresh chilled pork stored under controlled temperature over a 21-day period were evaluated with physico-chemical, sensory and microbiological analyses. Results showed that BOPPAcPVDC film provided better protection for fresh pork than BOPPcoex film in terms of physico-chemical, sensory and microbiological attributes, due to its greater barrier behaviour, with smaller permeance data (q) (0.98 to 324 cm3/m2 · d · bar) for BOPPAcPVDC, compared to BOPPcoex (227 to 6200 cm3/m2 · d · bar), in the temperature range from 4 °C to 60 °C (p < .001). The shelf life of fresh pork packed in this film was doubled, from 7 to 14 days.


Assuntos
Embalagem de Alimentos/métodos , Polímeros , /normas , Animais , Dióxido de Carbono/química , Microbiologia de Alimentos , Armazenamento de Alimentos/métodos , Humanos , Nitrogênio/química , Odorantes , Oxigênio/química , Permeabilidade , /microbiologia , Suínos , Temperatura Ambiente , Vácuo
19.
J Dairy Res ; 86(3): 354-360, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31328709

RESUMO

A commercial drinkable yogurt with and without 4% of added trehalose (as cell protectant) was spray-dried obtaining a powder with low water activity (aw). Total bacterial count in the powder was between 8.48-8.90 log cfu/g. The dried yogurt was stored: (i) at 38 °C and aw = 0.33; (ii) at 38 °C in hermetically sealed flasks (aw = 0.21/0.22); (iii) in a cyclic temperature chamber (10-20 °C) in hermetically sealed flasks (aw = 0.21/0.22). Whole milk was then fermented by adding an inoculum of spray-dried yogurt after storage under these different conditions. The kinetics of acidification showed the presence of a lag time which was strongly dependent on storage conditions. The data was fitted with a logistic type equation from which the lag time was calculated. To evaluate structural differences among samples, Fourier Transform Infrared spectra (FTIR) were recorded. Partial Least Squares (PLS) models enabled a good correlation between lag time of fermentation and FTIR spectra. The lag time for yogurt powder stored at aw about 0.21/0.22 and cyclic temperature 10-20 °C remained approximately constant over the 12 weeks of storage, while all the other conditions resulted in a dramatic increase. The addition of trehalose had a small influence on lag time and, therefore, as a protectant of lactobacilli.


Assuntos
Armazenamento de Alimentos/métodos , Leite/microbiologia , Iogurte/microbiologia , Animais , Contagem de Colônia Microbiana , Dessecação/métodos , Fermentação , Lactobacillus/efeitos dos fármacos , Lactobacillus/fisiologia , Pós , Fatores de Tempo , Trealose/administração & dosagem , Iogurte/análise
20.
Food Chem ; 299: 125138, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31302430

RESUMO

As an environmentally friendly approach for fruit quality improvement, the effect of preharvest UV-C on the physiology of strawberry fruit during postharvest storage remains to be assessed. Strawberry fruit developed with supplementary UV-C were stored at room temperature for 2 weeks. Preharvest UV-C attenuated fruit postharvest senescence and altered phytochemicals composition. Higher ester titer was found in the treated fruit at harvest, whereas higher terpene and furanone contents were detected after 72 h of storage. At harvest, polyphenolics accumulated to a higher level in UV-C group, but the difference disappeared after 24 h of storage. Meanwhile, the intrinsic level of abscisic acid and the expressions of FaPYR1, SnRK2, and FaASR in the UV-C-treated fruit was enhanced at harvest but returned to a lower level as storage proceeded. This study highlights the time-dependent effect of preharvest UV-C on strawberry fruit postharvest biochemical indexes and the possible involvement of abscisic acid signaling factors.


Assuntos
Ácido Abscísico/metabolismo , Armazenamento de Alimentos/métodos , Fragaria/fisiologia , Frutas/fisiologia , Compostos Fitoquímicos/metabolismo , Ácido Abscísico/genética , Fragaria/química , Fragaria/efeitos da radiação , Frutas/química , Frutas/metabolismo , Frutas/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Compostos Fitoquímicos/análise , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Polifenóis/análise , Polifenóis/metabolismo , Terpenos/análise , Terpenos/metabolismo , Raios Ultravioleta
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