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1.
Foods ; 13(6)2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38540939

RESUMO

The effect of exposure of soft wheat buns to Ultraviolet-C radiation (UV-C, 253.7 nm) was studied as an alternative to conventional treatments to control fungal spoilage and prolong shelf life. To identify the most suitable operating conditions, the study included preliminary tests on the permeability of films to UV-C irradiation, and on treatment antifungal efficacy on target microorganisms (Penicillium digitatum and Saccharomycopsis fibuligera) in Petri dishes. A 125 µm T9250B film (Cryovac® Sealed Air S.r.l), commercially available for long-life bread treated with ethanol and conditioned in a modified atmosphere, was selected to pack buns before the UV-C treatment. The study was carried out along with the observation of the fungal growth of buns artificially inoculated with suspensions of P. digitatum and S. fibuligera, treated under UV-C at a distance of 25 cm between bread and the 15 W UV-C source, in comparison to untreated buns used as control. Estimation of fungal growth as well as sensory evaluation was made 2, 4, 7, 10 and 14 days after the treatment. UV-C treated buns showed a noticeable reduction of fungal spoilage and kept a tender texture for up to two weeks after packaging. UV-C treatment represents a good opportunity for the bakery industry, reducing costs and ensuring a prolonged shelf life of a commercial product, respecting the health and hedonistic expectations of the customers.

2.
Foods ; 10(3)2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33801354

RESUMO

Two globe artichoke genotypes, "Spinoso sardo" and "Opera F1", have been processed as ready-to-cook (RTC) slices and refrigerated at 4 °C for 12 days (i) to evaluate the suitability to be processed as RTC slices; (ii) to evaluate the effect of a Foeniculum vulgare essential oil (EO) emitter, within an active package system, to delay quality decay, thus extending shelf life; (iii) to estimate the impact of EO emitter on the sensory profile of the RTC slices after cooking. Results revealed that both globe artichoke genotypes possess a good attitude to be processed as RTC product. "Opera F1" showed the best performances for color parameters, texture and chemical indexes, while "Spinoso sardo" showed lower mass loss (ML) over the storage time. The addition of EO emitter slowed down the consumption of O2, better preserved texture when compared to the control and more effectively control polyphenol oxidase (PPO) activity and antioxidants' retention during the cold storage. Microbial counts in control globe artichoke RTC slices were significantly higher than those packed with EO emitter, confirming the inhibiting role played by EO of F. vulgare. In addition, the EO emitter did not influence negatively the sensory profile of RTC globe artichoke slices after microwave cooking.

3.
J Sci Food Agric ; 99(11): 5219-5228, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31049967

RESUMO

BACKGROUND: The globe artichoke [Cynara cardunculus var. scolymus (L.) Fiori] is a natural source of minerals, fiber, inulin, and polyphenols. A ready-to-cook (RTC) version of this product could improve its commercialization and consumption. In this study, the effects of (i) anti-browning treatments (citric acid 0.5% + ascorbic acid 2%, or cysteine 0.5%, w/v) and (ii) dipping in locust bean gum (LBG) edible coating with or without Foeniculum vulgare essential oil (EO) were evaluated on RTC globe artichoke slices cv. 'Spinoso sardo' during storage (11 days at 4 °C). Fresh weight loss, color, texture, polyphenol oxidase (PPO), microbiological and chemical parameters, antioxidant capacity, and sensory descriptors were determined. RESULTS: The results showed that, despite the antioxidant treatment used, when EO was added to LBG, all microbiological groups underwent an average reduction of 0.50 log CFU g-1 . Cysteine preserved the antioxidant capacity, color, and texture of samples better than citric acid and ascorbic acid, and inhibited PPO; the addition of EO to LBG enhanced these effects. At the end of the storage period, the overall highest sensory attribute score was attained by the coated globe artichoke samples with EO. CONCLUSION: The marked efficacy of the LBG edible coating with added F. vulgare EO in maintaining microbiological, physical, chemical, and sensory qualities makes it a promising processing tool for the preservation of ready-to-cook Spinoso sardo globe artichoke slices during storage for 11 days at 4 °C. © 2019 Society of Chemical Industry.


Assuntos
Cynara scolymus/química , Fast Foods/análise , Foeniculum/química , Aditivos Alimentares/análise , Conservação de Alimentos/métodos , Óleos Voláteis/análise , Óleos de Plantas/análise , Cor , Culinária , Conservação de Alimentos/instrumentação , Humanos , Polifenóis/análise , Paladar
4.
J Sci Food Agric ; 97(2): 650-658, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27144811

RESUMO

BACKGROUND: Although nitrogen (N) fertilisation is essential for promoting crop yield, it may also affect the produce quality. Here, the influence of three N fertiliser rates (0 kg ha-1 as a control, 200 kg ha-1 and 400 kg ha-1 referred to as N0 , N200 and N400, respectively) on the overall quality of minimally processed globe artichoke heads was investigated during refrigerated storage for 12 days. RESULTS: Throughout the storage time, N fertilised samples had higher inulin contents than those unfertilised. In addition, the respiratory quotient of N200 and N400 samples was 2-fold and 2.5-fold lower than N0 ones, whose values were close to the normal range for vegetables. All the samples reported good microbiological standards, although N200 and N400 achieved lower mesophilic and psychotropic counts than N0 throughout the storage time. After 8 and 12 days of refrigerated storage, the N200 samples showed the highest scores of positive sensory descriptors. CONCLUSION: A fertiliser level of 200 kg N ha-1 is suitable for obtaining minimally processed globe artichoke heads with good nutritional, sensory and microbiological quality, characterised by low endogenous oxidase activities. Proper packaging systems and procedures are, however, crucial for extending the product shelf-life and, thus, promoting its exportation on a wider scale. © 2016 Society of Chemical Industry.


Assuntos
Produção Agrícola , Produtos Agrícolas/química , Cynara scolymus/química , Fertilizantes , Flores/química , Qualidade dos Alimentos , Ciclo do Nitrogênio , Carga Bacteriana , Catecol Oxidase/metabolismo , Respiração Celular , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/metabolismo , Produtos Agrícolas/microbiologia , Cynara scolymus/crescimento & desenvolvimento , Cynara scolymus/metabolismo , Cynara scolymus/microbiologia , Carboidratos da Dieta/análise , Flores/crescimento & desenvolvimento , Flores/metabolismo , Flores/microbiologia , Manipulação de Alimentos , Armazenamento de Alimentos , Bactérias Gram-Negativas/crescimento & desenvolvimento , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/crescimento & desenvolvimento , Bactérias Gram-Positivas/isolamento & purificação , Inulina/análise , Inulina/biossíntese , Valor Nutritivo , Pigmentos Biológicos/análise , Pigmentos Biológicos/biossíntese , Pigmentos Biológicos/metabolismo , Proteínas de Plantas/metabolismo , Refrigeração , Sensação , Propriedades de Superfície
5.
Food Chem ; 148: 47-53, 2014 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-24262525

RESUMO

The assessment of freshness of different sizes of blue fish (Engraulis encrasicolus 12 cm, Sardina pilchardus 15 cm, Trachurus trachurus 40 cm, Scomber japonicus colias 60 cm) was carried out using non-conventional enzymatic methods. The activities of the three lysosomal enzymes (α-glucosidase (AG), ß-galactosidase (B-GAL) and ß-N-acetylglucosamidase (B-NA)) in extracts of blue fish muscle were measured over a period of 21 days of storage. A significant increase (p<0.05) of AG activity was observed in all species, with a large increase seen after only one day of storage. B-NA activity increased slightly in sardines, horse mackerels and chub mackerel during frozen/thawed storage. Finally, the increase of B-GAL activity was significant (p<0.05) only in the samples of larger blue fish as horse mackerel and chub mackerel. All of these enzyme activities may be helpful predictive markers to limit fraud in these species.


Assuntos
Acetilglucosaminidase/análise , Manipulação de Alimentos/métodos , Lisossomos/enzimologia , Músculos/enzimologia , Alimentos Marinhos/análise , alfa-Glucosidases/análise , beta-Galactosidase/análise , Animais , Peixes/classificação , Armazenamento de Alimentos , Congelamento , Lisossomos/química , Região do Mediterrâneo , Músculos/química
6.
J Sci Food Agric ; 93(6): 1449-57, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23070982

RESUMO

BACKGROUND: The 'processing tomato' is an important source of natural antioxidants whose concentration depends, along with other parameters, on water availability. In order to better understand the mechanisms that regulate the response to water stress, a study was carried out in a typically semi-arid Mediterranean environment to investigate the yield, chemical composition and visual quality of tomato cv. 'Brigade' field grown under no irrigation (V0) in comparison with those of the conventional fully irrigated crop (V100). RESULTS: The stressful conditions of V0 affected the total yield. Nevertheless, fruits exhibited an increase in firmness (+27%), total solids (+23%) and total soluble solids (+5%). The dynamic balance between the antioxidant pattern and polyphenol oxidase activity under water stress conditions resulted in fruits with increased antioxidant activity (+12%), due to a decline in enzyme activity (-48%) and a rise in vitamin C (+20%) and total phenolic (+13%) contents. CONCLUSION: It is possible to manage water stress by applying water-saving irrigation strategies in order to promote the quality and nutritional properties of tomatoes while also contributing to saving water. This is a relevant aspect in processing tomato cultivation in semi-arid environments, where both the cost and availability of irrigation water represent a rising problem in agricultural activities.


Assuntos
Antioxidantes/metabolismo , Catecol Oxidase/metabolismo , Clima , Secas , Frutas , Solanum lycopersicum , Água , Irrigação Agrícola , Ácido Ascórbico/metabolismo , Biomassa , Conservação dos Recursos Naturais , Dieta , Qualidade dos Alimentos , Frutas/química , Frutas/enzimologia , Frutas/fisiologia , Frutas/normas , Dureza , Humanos , Solanum lycopersicum/química , Solanum lycopersicum/enzimologia , Solanum lycopersicum/fisiologia , Região do Mediterrâneo , Fenóis/metabolismo , Estresse Fisiológico
7.
J Agric Food Chem ; 56(1): 132-8, 2008 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-18069784

RESUMO

Polyphenol oxidase (PPO) and peroxidase (POD) were extracted from two different varieties of melon ( Cucumis melo L. cantalupensis cv. Charentais and C. melo L. inodorus cv. Amarillo) and characterized using reliable spectrophotometric methods. In both cases the enzymes followed Michaelis-Menten kinetics, showing different values of kinetics parameters between the two cultivars: K m = 7.18 +/- 0.70 mM ('Charentais') and 6.66 +/- 0.20 mM ('Amarillo') mM; V max = 7.93 +/- 0.35 units/min ('Charentais') and 13.82 +/- 0.37 units/min ('Amarillo'), relative to PPO; K m = 24.0 +/- 2.10 mM ('Charentais') and 5.05 +/- 0.19 mM ('Amarillo') mM; V max = 344.83 +/- 10.32 units/min ('Charentais') and 80.64 +/- 2.01 units/min ('Amarillo'), relative to POD. Optimum pH for PPO was 7.0 for 'Charentais' and 7.5 for 'Amarillo, whereas it was 4.5 for both cultivars relative to POD. Melon PPO had maximum activity at 60 degrees C in both 'Charentais' and 'Amarillo' cultivars, whereas POD maximum activity was found at 45 degrees C in 'Charentais' and at 25 degrees C in 'Amarillo'. POD from both cultivars showed higher thermolability compared with PPO, losing >90% of relative activity after only 5 min of incubation at 70 degrees C. POD's activation energy was much higher than that of PPO (Delta E (#) = 86.3 and 160.6 kJ mol (-1) for 'Charentais' and 'Amarillo', respectively). PPO and POD activities from both cultivars showed a decreasing pattern as sugar concentration in the assay medium increased, except in POD extract from 'Charentais', which maintained its activity in the presence of high d-glucose concentration (up to 5 M). Changes in L*, a*, b*, chroma, and hue angle values were chosen to describe the browning development in the samples during storage at 5 degrees C. A slight decrease in L* value and a more marked reduction of a* value were noted in both cultivars above all at the end of storage period. POD activity during storage at 5 degrees C was highly correlated with changes of parameters a*, b*, chroma, and hue angle ( r (2) from 0.82 to 0.97) for cultivar 'Charentais'. According to these results, only POD activity seemed to be involved in browning of minimally processed melon.


Assuntos
Catecol Oxidase/metabolismo , Cucumis melo/enzimologia , Reação de Maillard , Peroxidase/metabolismo , Fenômenos Químicos , Físico-Química , Inibidores Enzimáticos/farmacologia , Estabilidade Enzimática , Temperatura Alta , Cinética , Termodinâmica
8.
J Agric Food Chem ; 55(9): 3469-76, 2007 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-17407312

RESUMO

Polyphenol oxidase and peroxidase were extracted from two different varieties of strawberry fruit (Fragaria x ananassa D, cv. 'Elsanta' and Fragaria vesca L, cv. 'Madame Moutot') and characterized using reliable spectrophotometric methods. In all cases, the enzymes followed Michaelis-Menten kinetics, showing different values of peroxidase kinetics parameters between the two cultivars: Km = 50.68 +/- 2.42 mM ('Elsanta') and 18.18 +/- 8.79 mM ('Madame Moutot') mM and Vmax = 0.14 +/- 0.03 U/g ('Elsanta') and 0.05 +/- 0.01 U/g ('Madame Moutot'). The physiological pH of fruit at the red ripe stage negatively affected the expression of both oxidases, except polyphenol oxidase from 'Madame Moutot' that showed the highest residual activity (68% of the maximum). Peroxidase from both cultivars was much more thermolable as compared with PPO, losing over 60% of relative activity already after 60 min of incubation at 40 degrees C. The POD activation energy was much lower than the PPO activation energy (DeltaE = 97.5 and 57.8 kJ mol-1 for 'Elsanta' and 'Madame Moutot', respectively). Results obtained from d-glucose and d-fructose inhibition tests evidenced a decreasing course of PPO and POD activities from both cultivars as the sugar concentration in the assay medium increased. Changes in CIE L*, a*, b*, chroma, and hue angle values were taken as a browning index of the samples during storage at 4 degrees C. A decrease in L* was evident in both cultivars but more marked in 'Elsanta'. PPO and POD activities from cv. 'Elsanta' were very well-correlated with the parameter L* (r2=0.86 and 0.89, respectively) and hue angle (r2=0.85 and 0.93, respectively). According to these results, the browning of the fruit seemed to be in relation to both oxidase activities.


Assuntos
Catecol Oxidase/metabolismo , Temperatura Baixa , Fragaria/enzimologia , Frutas/enzimologia , Reação de Maillard , Peroxidase/metabolismo , Inibidores Enzimáticos/farmacologia , Conservação de Alimentos/métodos , Frutas/química , Cinética , Termodinâmica
9.
J Agric Food Chem ; 53(6): 2032-8, 2005 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-15769132

RESUMO

Polyphenol oxidase (PPO) was extracted from five Sicilian varieties of tomato fruit [Pizzutello, Naomi (Hazera), F1 PS212 (Peto seed), Rosa Maletto, and PO228] and assayed with a method using 3-methylbenzothyazolinone hydrazone (MBTH) as chromophore coupling agent. 3,4-Dihydroxyphenylacetic acid was chosen for tomato PPO activity determination. The tomato PPO had maximum activity at pH 4.8. The pH of juice in ripe fruits is between 4.1 and 4.4, a range in which PPO relative activity is between 74 and 87%. The optimum temperature of activity for tomato PPO was 40 degrees C; the enzyme showed a good relative activity (55% of the maximum) at cold-storage temperature (4 degrees C). PPO retained 82% relative activity at an NaCl concentration of 0.1 M; at higher concentrations the PPO became gradually inactivated. The commercial variety Naomi is more susceptible to enzymatic browning than the local varieties Pizzutello, Rosa Maletto and PO228, due to higher PPO activity levels. This result confirms the suitability of these local tomato varieties to national markets. Results from storage tests seem to relate PPO activity with color changes associated with browning and lycopene degradation, because lycopene is an antioxidant agent that reconstitutes the polyphenols oxidized by the action of PPO.


Assuntos
Carotenoides/análise , Catecol Oxidase/metabolismo , Frutas/enzimologia , Reação de Maillard , Solanum lycopersicum/enzimologia , Fenômenos Químicos , Físico-Química , Inibidores Enzimáticos/farmacologia , Estabilidade Enzimática , Frutas/química , Concentração de Íons de Hidrogênio , Cinética , Licopeno , Solanum lycopersicum/química , Cloreto de Sódio/farmacologia , Especificidade por Substrato , Temperatura
10.
Appl Biochem Biotechnol ; 101(1): 1-13, 2002 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12008863

RESUMO

Beta-D-Glucopyranosidase (betaG, EC 3.2.1.21) has been isolated from some collateral activities, alpha-L-arabinofuranosidase (Ara, EC 3.2.1.55), alpha-L-rhamnopyranosidase (Rha, EC 3.2.1.40), and o-acetylesterase (Est, EC 3.1.1.53), using a commercial enzyme preparation and a simple method economically sustainable for the food industry. The procedure comprises precipitation of extraneous substances by adding ethanol and CaCl2, ultrafiltration, and adsorption, first on bentonite and then on chitosan. The results obtained were the complete isolation of betaG from the above-mentioned activities, a drastic reduction in extraneous compounds, such as brown substances and polysaccharides, and a slight increase in purification.


Assuntos
Glicosídeo Hidrolases/isolamento & purificação , beta-Glucosidase/isolamento & purificação , Acetilesterase/isolamento & purificação , Acetilesterase/metabolismo , Adsorção , Precipitação Química , Técnicas de Química Analítica/métodos , Etanol/química , Glicosídeo Hidrolases/metabolismo , Polissacarídeos/isolamento & purificação , Especificidade por Substrato , beta-Glucosidase/metabolismo
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