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1.
Phytochem Anal ; 35(4): 903-922, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38403936

RESUMO

INTRODUCTION: The safety and quality of many medicinally important herbs are compromised since farmers and small organizations are involved in the cultivation, aggregation, and primary processing of these herbs. Such organizations often lack adequate quality control facilities. To improve the safety and quality of herbal products, simple, rapid, and affordable quality control systems are required. OBJECTIVES: The aim of this study was to assess the suitability of microwave oven-drying for moisture content (MC) determination and sample preparation of herbs in small organizations. METHODS: Microwave oven-drying (720 W) and convective oven-drying at 105°C for MC determination were compared. The effects of three different drying methods (microwave oven-drying, low-temperature convective drying, and freeze-drying) on in vitro antioxidant and polyphenol oxidase (PPO) activity were determined, similarity analysis was conducted using HPLC signature spectra, and validation was performed with LC-MS focusing on one herb. RESULTS: Microwave oven-drying at 720 W significantly reduced the drying time (from hours to minutes), whereas the spatial variation of temperature in convective ovens set at 105°C can cause about 10% underestimation of MC. Microwave oven-drying showed similar macro-properties like freeze-drying and higher extractability (10%-20%) and in vitro antioxidant capacity (33%-66%) and lower PPO activity compared to low-temperature convective drying. HPLC signature spectra revealed strong similarity of soluble components between freeze-dried and microwave oven-dried herbs. LC-MS analysis demonstrated more common compounds between freeze-dried and microwave oven-dried Centella asiatica extracts, whereas convective tray-dried samples had fewer compounds common with samples obtained by freeze-drying or microwave oven-drying. CONCLUSIONS: Microwave oven-drying is rapid (tens of min) and shows small batch-to-batch variation compared to oven-drying at 105°C. The in vitro antioxidant assays and signature spectra can be used for assessing the source and purity or quality of a specific herb variety.


Assuntos
Antioxidantes , Dessecação , Liofilização , Micro-Ondas , Plantas Medicinais , Controle de Qualidade , Plantas Medicinais/química , Antioxidantes/análise , Antioxidantes/química , Dessecação/métodos , Liofilização/métodos , Cromatografia Líquida de Alta Pressão/métodos , Catecol Oxidase/análise
2.
Curr Opin Biotechnol ; 81: 102921, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36965297

RESUMO

Significant amounts of fresh and fresh-cut fruits and vegetables are wasted every year due to enzymatic browning. Polyphenol oxidase (PPO) is the key enzyme involved in the enzymatic browning. In the past decades, various methods have been developed to inhibit browning of various fresh produce items. However, for most fresh horticultural produce, ideal measures accepted by industries and consumers are still scarce. This review provides up-to-date knowledge of browning control technologies, including physical methods, chemical methods such as natural inhibitors, molecular biotechnology, and nanotechnology. In addition, we propose some ideas to improve the efficacies of these strategies with fewer side effects. To better inhibit tissue browning, new research directions are also discussed, for example, regulation of PPO substrate techniques.


Assuntos
Catecol Oxidase , Frutas , Catecol Oxidase/análise , Catecol Oxidase/química , Frutas/química , Biotecnologia
3.
J Sci Food Agric ; 102(1): 121-131, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34060085

RESUMO

BACKGROUND: The present study investigated the sensory acceptance, oxidative damage and protection, and possible anatomical-structural damage of cells from the surface of shapes of minimally processed yam. The tubers were minimally processed into the peeled rondelle, dice and 'chateau cut' (chateau) shapes, the latter of which was obtained after performing the abrasion technique. Control treatment corresponded to the rondelle shape with the periderm. The pieces were kept packed at 5 ± 2 °C for 14 days. RESULTS: Peeled rondelle and chateau were sensorially the most well-accepted yam shapes and achieved the highest purchase intention. The enzymes were partially modulated by the detected H2 O2 levels. Oxidative burst lasted longer in the minimally processed tissues than in the control. Polyphenol oxidase activity showed a clear difference in behavior between the minimally processed pieces and the control. Minimal processing induced transient increases in phenolic compounds, for which the expression was lowest in the abraded pieces. On the other hand, these pieces exhibited greater cell collapse on the surface of the amyliferous parenchyma. CONCLUSION: Based on the results of the trained panel, the abrasion technique is an alternative to provide shapes that are better accepted and marketable, more resistant to browning, and can be stored for up to 12 days. Resistance to browning may be related to a more efficient modulation of enzymatic antioxidant systems and intense deposition of cell debris on the surface of the amyliferous parenchyma. © 2021 Society of Chemical Industry.


Assuntos
Comportamento do Consumidor , Dioscorea/química , Manipulação de Alimentos/métodos , Catecol Oxidase/análise , Catecol Oxidase/metabolismo , Dioscorea/metabolismo , Manipulação de Alimentos/instrumentação , Humanos , Fenóis/análise , Fenóis/metabolismo , Tubérculos/química , Tubérculos/metabolismo
4.
J Sci Food Agric ; 101(13): 5608-5617, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33709503

RESUMO

BACKGROUND: The change of surface color caused by browning during the drying process of shiitake mushrooms seriously affects its market circulation. Intensive pulsed light (IPL) as a non-heat-treatment method can reduce enzyme activity by changing the enzyme structure. Therefore, in this study, the use of IPL pretreatment before drying was aimed to reduce the adverse reactions caused by the browning reaction during the drying processing of shiitake mushrooms. RESULTS: Shiitake mushrooms pretreated with 25 pulses of IPL energy of 400 J reduced the initial polyphenol oxidase enzyme activity, the browning index, and browning degree values by 42.83%, 43.02%, and 47.54% respectively. The IPL pretreatment enhanced the polysaccharides and reducing sugars contents and it reduced 5-hydroxymethylfurfural generation in the dried shiitake mushrooms. The pretreatment also improved the surface color, the antioxidant activity, and retained the umami taste characteristics in the dried shiitake mushroom. CONCLUSION: The IPL pretreatment combined with controlled temperature and humidity for convection drying could be a suitable method to improve the quality of dried shiitake mushrooms. Therefore, this study provides a new pretreatment method for materials that are prone to browning during drying. © 2021 Society of Chemical Industry.


Assuntos
Dessecação/métodos , Conservação de Alimentos/métodos , Cogumelos Shiitake/química , Cogumelos Shiitake/efeitos da radiação , Antioxidantes/análise , Catecol Oxidase/análise , Cor , Dessecação/instrumentação , Conservação de Alimentos/instrumentação , Proteínas Fúngicas/análise , Furaldeído/análogos & derivados , Furaldeído/análise , Umidade , Luz , Controle de Qualidade , Temperatura
5.
Food Chem ; 347: 129012, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33486359

RESUMO

The present study evaluated impact of pre-harvest foliar spraying with chitosan (2.0% and 3.0%) and post-harvest Aloe vera gel (AVG) coating (25% and 33%) to determine the quality of table grape during storage. The results showed that both treatments significantly influenced the storage lifetime of this fruit. In addition, the chitosan and AVG combinations minimized the incidence of decay and reduced the weight loss more than that of chitosan, AVG and control samples. 25 days once the foliar application of chitosan 3.0% with AVG 33% coating extending the storage life of fruit up to 15 days by significantly reducing decay index, malondialdehyde, weight loss and polyphenol oxidase also, maintaining the overall quality index, firmness, antioxidant capacity, peroxidase, total phenols, anthocyanin, SSC and vitamin C. Based on the findings, these natural compound treatments could be considered as suitable alternatives to extend the marketable period of table grapes and minimize post-harvest losses.


Assuntos
Quitosana , Armazenamento de Alimentos/métodos , Frutas/química , Preparações de Plantas , Vitis/química , Antocianinas/análise , Antioxidantes/análise , Ácido Ascórbico/análise , Catecol Oxidase/análise , Malondialdeído/análise , Fenóis/análise
6.
Microbiol Res ; 237: 126482, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32353683

RESUMO

Seed biopriming is an emerging technique to enhance seed germination under stress conditions. An integrated approach of tomato seed biopriming with ascorbic acid, Trichoderma asperellum BHU P-1 and Ochrobactrum sp. BHU PB-1 was applied to observe the response against wilt pathogen of tomato Fusarium oxysporum f. sp. lycopersici (FOL). Tomato seeds bioprimed with the aforementioned application expressed augmented seed germination and activated of defense response. Seed germination was recorded higher (80 %) at low concentration (1 pM) of ascorbic acid as compared to high concentration of 1 mM (41 %). Combination of both ascorbic acid and antagonistic microbe treatments (T5 & T6) significantly reduced disease incidence (up to 28 %) in tomato plants at 10 days. T5 and T6 treated plants exhibited higher accumulation of total phenol content and increased activity of Phenylammonia lyase (PAL), Peroxidase (PO), Chitinase (Chi) and Polyphenol oxidase (PPO) as compared to control (T1) plants. ROS formation in the form of H2O2 was also found to be reduced in combined treatment. Histochemical analysis revealed that phenylpropanoid pathway (lignin deposition) was more activated in combined priming treatment plants as compared to individual treatment upon challenge inoculation with FOL. Transcript expression analysis of defense genes confirmed the up-regulation of PAL (2.1 fold), Chi (0.92 fold), Pathogenesis related proteins (PR) (1.58 fold) and Lipoxygenase (Lox) (0.72 fold) in T6 treatment as compared to T1 treatment plants at 96 h. This study reveals that ascorbic acid treatment with antagonistic microbes through seed priming effectively induced seed germination and elicited defense mechanism to control wilt disease in tomato plants.


Assuntos
Antibiose , Resistência à Doença , Fusariose/prevenção & controle , Sementes , Solanum lycopersicum , Ácido Ascórbico/farmacologia , Agentes de Controle Biológico/farmacologia , Catecol Oxidase/análise , Quitinases/análise , Resistência à Doença/genética , Fusariose/tratamento farmacológico , Fusarium/efeitos dos fármacos , Fusarium/patogenicidade , Expressão Gênica , Genes de Plantas , Peróxido de Hidrogênio/análise , Hypocreales , Lignina/metabolismo , Solanum lycopersicum/crescimento & desenvolvimento , Solanum lycopersicum/metabolismo , Solanum lycopersicum/microbiologia , Ochrobactrum , Fenol/análise , Compostos de Fenilamônio/análise , Doenças das Plantas/prevenção & controle , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Sementes/microbiologia
7.
Molecules ; 24(23)2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31810325

RESUMO

In order to develop a simple, reliable and low cost enzymatic method for the determination of phenolic compounds we studied polyphenol oxidase activity of crude eggplant (S. melongena) extract using 13 phenolic compounds. Catechol, caffeic and chlorogenic acids, and L-DOPA have been rapidly oxidized with the formation of colored products. Monophenolic compounds have been oxidized at a much slower speed. Ferulic acid, quercetin, rutin, and dihydroquercetin have been found to inhibit polyphenol oxidase activity of crude eggplant extract. The influence of pH, temperature, crude eggplant extract amount, and 3-methyl-2-benzothiazolinone hydrazone (MBTH) concentration on the oxidation of catechol, caffeic acid, chlorogenic acid, and L-DOPA has been investigated spectrophotometrically. Michaelis constants values decrease by a factor of 2 to 3 in the presence of MBTH. Spectrophotometric (cuvette and microplate variants) and smartphone-assisted procedures for phenolic compounds determination have been proposed. Average saturation values (HSV color model) of the images of the microplate wells have been chosen as the analytical signal for smartphone-assisted procedure. LOD values for catechol, caffeic acid, chlorogenic acid, and L-DOPA equaled 5.1, 6.3, 5.8 and 30.0 µM (cuvette procedure), 12.2, 13.2, 13.2 and 80.4 µM (microplate procedure), and 23.5, 26.4, 20.8 and 120.6 µM (smartphone procedure). All the variants have been successfully applied for fast (4-5 min) and simple TPC determination in plant derived products and L-DOPA determination in model biological fluids. The values found with smartphone procedure are in good agreement with both spectrophotometric procedures values and reference values. Using crude eggplant extract- mediated reactions combined with smartphone camera detection has allowed creating low-cost, reliable and environmentally friendly analytical method for the determination of phenolic compounds.


Assuntos
Fenóis/análise , Compostos Fitoquímicos/análise , Extratos Vegetais/análise , Extratos Vegetais/química , Smartphone , Solanum melongena/química , Espectrofotometria , Ácidos Cafeicos/análise , Catecol Oxidase/análise , Catecol Oxidase/química , Catecóis/análise , Ativação Enzimática , Levodopa/análise , Espectrofotometria/métodos , Especificidade por Substrato
8.
Food Sci Technol Int ; 25(8): 711-722, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31291761

RESUMO

This research explores the cell wall composition and polyphenol oxidase activity of two pawpaw (Asimina triloba) fruit varieties, Susquehanna and Green River Belle, that were subjected to high pressure processing and 45 days of refrigerated storage. We hypothesize that high pressure processing may inhibit enzymatic action responsible for pawpaw's deleterious postharvest tissue softening and browning. Glycome profiling uses mAb groupings that recognize 19 groups of glycan epitopes present in most major classes of cell wall glycans and was used to determine cell wall composition. Results show that both varieties have typical type I primary cell walls of flowering dicots. However, differences in the fine cell wall structure between the varieties can be inferred and the varieties behaved differently during refrigerated storage, likely indicating of a difference in cell wall-modifying enzymes present in the primary cell walls. High pressure processing treatment does not seem to be effective at eliminating polyphenol oxidase activity.


Assuntos
Asimina/química , Catecol Oxidase/análise , Parede Celular/química , Epitopos , Frutas/química , Polissacarídeos/análise , Cor , Dureza , Concentração de Íons de Hidrogênio , Extratos Vegetais/análise , Pressão , Açúcares/análise
9.
J Food Biochem ; 43(5): e12832, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31353512

RESUMO

The effect of ultrasound (US), osmotic dehydration (OD), and osmosonication (OS) pretreatments on total phenolic content (TPC), total flavonoids content, (TFC), phytochemical constituents (gingerol derivatives and diarylheptanoids), polyphenol oxidase (PPO), peroxidase (POD), 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), cupric ion reducing capacity (CUPRAC), 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power capacity (FRAP), and color of ginger slices dried under relative humidity convective dryer was investigated. OS pretreatment improved the preservation of TPC (13.80-34.79 mg GAE/g d.w), TFC (26.46-62.16 mg CE/g d.w), ABTS (30.37%-86.10%), CUPRAC (36.89-73.97 mg/g), DPPH (50.57%-92.60%), FRAP (26.44-83 mg/g), and phytochemical constituents than US and OD. The OS-treated sample was more effective in inactivating both PPO (12.09%-35.93%) and POD (16.21%-39.58%) enzymes compared to US and OD-treated samples. However, US pretreatment retained the color quality of dried ginger slices than the OS and OD treatments. OS pretreatment (5.43) also increased the total color change (ΔE) of the dried ginger samples compared to US (2.81) and OD (4.60). PRACTICAL APPLICATIONS: Ginger is commonly used in the food, beverage, and pharmaceutical industries owing to their distinctive flavor and various health potentials. However, its high moisture content makes its inappropriate for long-term storage which results in its high perishability. Drying is one of the most common techniques to prolong its shelf life. Hence, any pretreatment for ginger that reduces the moistures content and lessens the drying time by preserving the quality of the crop is of vital importance. Ultrasound, osmotic dehydration, and osmosonication are novel pretreatment techniques that are widely used prior to drying of various agricultural products due to its numerous advantages over conventional methods. Its application in drying of foods could help shorten the drying time, reduce processing costs, improve energy consumption and efficiency, and preserve the physical and nutritional properties of the dried product. The current findings will also offer more information for selecting pretreatment techniques for ginger drying.


Assuntos
Antioxidantes/química , Flavonoides/análise , Fenóis/análise , Compostos Fitoquímicos/química , Zingiber officinale/química , Antioxidantes/metabolismo , Catecol Oxidase/análise , Catecóis/química , Catecóis/metabolismo , Cor , Dessecação , Álcoois Graxos/química , Álcoois Graxos/metabolismo , Flavonoides/metabolismo , Osmose , Peroxidase/análise , Fenóis/metabolismo , Compostos Fitoquímicos/metabolismo , Sonicação , Ondas Ultrassônicas
10.
J Food Sci ; 84(7): 1730-1736, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31218701

RESUMO

With high phytochemical and starch contents, purple-fleshed sweetpotatoes (PFSP) have been processed into various functional ingredients and food products including juices and natural colorants. For juice processing, PFSP are usually subjected to heat treatment for inactivation of pigment-degrading enzymes. However, heating of sweetpotatoes gelatinizes starch and produces thick slurry with cooked flavor, which are the drawbacks. Development of alternative processes to overcome the stated problems will be beneficial to sweetpotato processors. This study demonstrated that acidified water (≥3% w/v citric acid) was effective in inhibiting polyphenol oxidase and peroxidase in raw PFSP resulting in an attractive reddish juice. About 93% total phenolics (TP) and 83% total monomeric anthocyanins (TMA) in PFSP were extracted by two repeated extractions. The combined PFSP juice (3.2 L/kg PFSP) had high levels of TP (1,850 mg/L) and TMA (475 mg/L). With the developed process, 167 g dried starch, and 140 g dried high-fiber pomace were obtained for each kg raw PFSP, besides the highly pigmented juice. Pasteurization of the PFSP juice samples (pH 3.2) at 80 °C for 12 s resulted in 15% loss in TMA and had no effect on TP. The results indicated an efficient process to produce sweetpotato juice with high bioactive compounds and recovery of starch and high dietary fiber pomace as co-products. PRACTICAL APPLICATION: Purple-fleshed sweetpotatoes (PFSP) are rich in polyphenolics and antioxidant activities. In PFSP juice extraction, heat treatment to inactivate the pigment-degrading enzymes results in starch gelatinization and cooked flavor. A nonthermal process using acidified water was developed for producing anthocyanin-rich juice from PFSP and concurrently recovering native starch and dried pomace, which would increase the economic feasibility of the developed process. The results demonstrate an efficient process for the sweetpotato industry in producing PFSP pigmented juice and co-products for various food applications.


Assuntos
Ácidos/química , Antocianinas/análise , Catecol Oxidase/antagonistas & inibidores , Sucos de Frutas e Vegetais/análise , Ipomoea batatas/química , Peroxidase/antagonistas & inibidores , Extratos Vegetais/análise , Proteínas de Plantas/antagonistas & inibidores , Antocianinas/isolamento & purificação , Catecol Oxidase/análise , Cor , Culinária , Fibras na Dieta/análise , Ipomoea batatas/enzimologia , Peroxidase/análise , Fenóis/análise , Fenóis/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Proteínas de Plantas/análise , Amido/análise
11.
J Food Sci ; 84(5): 1078-1086, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30958915

RESUMO

Distribution of polyphenoloxidase (PPO) from different anatomical parts of Pacific white shrimp was examined. Among all parts, cephalothorax possessed the maximal PPO activity (P < 0.05), followed by pereopods, telson, pleopods, carapace, cuticle, and muscle, respectively. The higher PPO activity in cephalothorax was in line with the greater melanosis in this part during chilled storage. According to activity-staining toward 3,4-dihydroxy-ʟ-phenylalanine (ʟ-DOPA), PPO exhibited an activity band with a molecular weight (MW) of 210 kDa. When cephalothorax PPO was purified using ammonium sulfate precipitation and a series of chromatographic techniques, involving DEAE-Sepharose anion exchange and Sephadex G-75 gel filtration columns, homogeneity was obtained. Based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and native-PAGE, the Sephadex G-75 fraction showed a single band. The MW band on SDS-PAGE and gel filtration was estimated as 210 kDa, suggesting a monomeric molecule. For the inhibitor study, cysteine and 4-hexylresorcinol showed competitive inhibition toward PPO, while epigallocatechin gallate and kojic acid demonstrated mixed-type inhibition toward PPO. PRACTICAL APPLICATION: Melanosis (black spot formation) triggered by polyphenoloxidase (PPO) drastically reduces the shelf-life of shrimp. PPO was localized in several anatomical parts of Pacific white shrimp with varying activities. Certain compounds, including cysteine, 4-hexylresorcinol, epigallocatechin gallate, and kojic acid, showed PPO inhibitory activity with different modes of inhibition. The obtained information provided a promising method for manufacturers to keep the prime eating quality of Pacific white shrimp throughout postmortem transportation and storage using selected PPO inhibitors.


Assuntos
Catecol Oxidase , Penaeidae/enzimologia , Alimentos Marinhos/análise , Animais , Catecol Oxidase/análise , Catecol Oxidase/química , Catecol Oxidase/metabolismo , Distribuição Tecidual
12.
J Sci Food Agric ; 99(11): 5229-5238, 2019 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-31021408

RESUMO

BACKGROUND: In this study, fresh pistachio was exposed to UV-C irradiation (2.1 and 4.5 kJ m-2 ) in a rotating cylindrical system with seven germicidal UV-C lamps and immediately packed in perforated and non-perforated polyethylene terephthalate (PET). The fruit were evaluated for weight loss, total phenolic content, enzyme activities, color indices (L*, a*, b* and browning index), and microbial counts during 35 days of storage at 4 °C. RESULTS: UV-C treatment caused a significant decrease (P < 0.05) in the weight loss of fresh pistachios compared to the control. The activity of catalase and peroxidase enzymes was significantly higher (P < 0.05) in irradiated samples packed in non-perforated PET in comparison to those of untreated samples. Irradiation did not inhibit the activity of polyphenol oxidase in treated samples, although a slight decrease in polyphenol oxidase activity was observed in irradiated samples compared to control. The fruit treated with 2.1 kJ m-2 of UV-C and the control packed in non-perforated PET were lighter (L*), redder (a*), and less yellow (b*) compared to 4.5 kJ m-2 treated samples. Furthermore, a dose of 4.5 kJ m-2 UV-C significantly decreased sensory attributes of fresh pistachios compared to the other irradiation level and control. CONCLUSION: UV-C irradiation at a dose of 2.1 kJ m-2 and packing in non-perforated PET are recommended for fresh pistachio preservation based on the physicochemical, microbial, and sensory parameters. © 2019 Society of Chemical Industry.


Assuntos
Irradiação de Alimentos/métodos , Embalagem de Alimentos/métodos , Frutas/efeitos da radiação , Pistacia/química , Catecol Oxidase/análise , Embalagem de Alimentos/instrumentação , Armazenamento de Alimentos , Frutas/química , Humanos , Pistacia/efeitos da radiação , Proteínas de Plantas/análise , Controle de Qualidade , Paladar , Raios Ultravioleta
13.
Food Chem ; 286: 600-607, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-30827652

RESUMO

This study investigated the effectiveness of cysteine in conservation of bioactive compounds and the antioxidant capacity of minimally processed red beet. After red beet minimal processing increasing cysteine concentrations were applied, corresponding to control, 2 mM, 4 mM, 8 mM and 16 mM. Assay was performed over 15 d to evaluate the polyphenols, betalains, antioxidant capacity and enzymatic activity of polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL). Cysteine enhanced the gallic acid, caffeic acid, chlorogenic acid, kaempferol and betalain contents until 6 d of storage. Subsequently, dosages of cysteine above 4 mM maintained gallic acid, kaempferol and betalains contents. Cysteine appears to influence the phenylpropanoid pathway, favoring the accumulation of polyphenols and betalains. In red beet, cysteine did not inhibit PPO activity but enhanced PAL activity. Betalains contribute more than phenolics to the antioxidant capacity, and their relationship with cysteine has not been thoroughly elucidated to date.


Assuntos
Beta vulgaris/química , Betalaínas/análise , Cisteína/farmacologia , Conservação de Alimentos/métodos , Polifenóis/análise , Antioxidantes/análise , Beta vulgaris/efeitos dos fármacos , Beta vulgaris/metabolismo , Ácidos Cafeicos/análise , Ácidos Cafeicos/metabolismo , Catecol Oxidase/análise , Catecol Oxidase/metabolismo , Ácido Gálico/análise , Ácido Gálico/metabolismo , Fenilalanina Amônia-Liase/análise , Fenilalanina Amônia-Liase/metabolismo , Proteínas de Plantas/análise , Proteínas de Plantas/metabolismo
14.
Int J Food Sci Nutr ; 70(6): 688-700, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30704309

RESUMO

The present work studied the effect of the year of harvest, the genotype and the cultivation method on the nutritional quality and the allergen content of three plum cultivars. The common quality parameters and the phytochemical content strongly varied with the year and the cultivar, while the system of cultivation had a minor influence. In particular, ascorbic acid greatly decreased in 2016 compared to 2015, while polyphenols were higher in 2016. The health-promoting compounds, and particularly phenolics, were significantly correlated with the antioxidant capacity. Finally, the allergen content was strongly dependent on the content of flavan-3-ols, suggesting that this class of phenolics is determinant in influencing the allergen content in plums. Results showed that the major factor affecting the quality and the concentration of natural metabolites of plum, in addition to the diversity among genotypes, is the year-to-year variation, whereas the system of cultivation plays a marginal role.


Assuntos
Alérgenos/análise , Genótipo , Agricultura Orgânica , Prunus domestica/química , Prunus domestica/crescimento & desenvolvimento , Antígenos de Plantas/análise , Antígenos de Plantas/genética , Antioxidantes/análise , Ácido Ascórbico/análise , Catecol Oxidase/análise , Frutas/química , Compostos Fitoquímicos/análise , Extratos Vegetais/química , Proteínas de Plantas/análise , Polifenóis/análise , Prunus domestica/genética , Estações do Ano , Tempo (Meteorologia)
16.
Food Chem ; 276: 494-502, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30409624

RESUMO

The optimum thermosonication parameters, temperature and ultrasound energy density (UED), determined by using response surface methodology to inactivate polyphenol oxidase (PPO) and protecting the quality parameters, especially color of strawberry nectar. The PPO inactivation was successfully achieved by thermosonication treatment. Increasing of temperature resulted with decreasing of browning index and increasing of hydroxymethyl furfural. High temperature-low UED combination can be applied to obtain minimum change in ΔE∗ and maximum protection of ascorbic acid. Thermosonication at mild temperature (∼50 °C) and UED (∼230 J/g) ensured the maximum levels of total monomeric anthocyanin and total phenolic content. The combination of 59 °C and 455 J/g was the conditions of optimum thermosonication to minimize quality parameters which cause undesirable changes like color degradation in nectar and maximize desirable ones which have beneficial effects on characteristics of nectar or on human health like phenolic content of nectar.


Assuntos
Manipulação de Alimentos/métodos , Qualidade dos Alimentos , Fragaria/química , Temperatura Alta , Néctar de Plantas/química , Sonicação/métodos , Antocianinas/análise , Ácido Ascórbico , Catecol Oxidase/análise , Cor , Fenóis/análise
17.
J Sci Food Agric ; 98(14): 5378-5385, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29660118

RESUMO

BACKGROUND: The objective of the present work was to study the effect of high-power ultrasound (HPU) on the microflora, enzymes and some quality attributes of a strawberry drink and to provide a theoretical basis for strawberry drink processing conducive to the development of more nutritious and healthier strawberry drinks. RESULTS: Fresh strawberry drink was subjected to HPU treatment at 20 kHz (242, 605 and 968 W cm-2 ) for 2, 4, 6, 8 and 10 min in an ice bath. Results showed that polyphenol oxidase (PPO), pectin methyl esterase (PME) and ß-glucosidase activities were decreased by 44.90, 89.11 and 84.71% respectively at 968 W cm-2 for 10 min. Lower L*, a* and b* values and higher browning degree (BD) were observed in HPU-treated samples, resulting in a significant increase in ΔE value (P < 0.05). HPU treatment caused loss of viscosity and turbidity, while total soluble solids (TSS) and pH of the strawberry drink were stable. Total phenol content and antioxidant capacity increased while anthocyanin content decreased compared with untreated samples. Total aerobic bacteria (TAB) and molds and yeasts (M&Y) were reduced by 2.07 and 1.13 log10 cycles respectively at 968 W cm-2 for 10 min. CONCLUSIONS: HPU can effectively achieve the effect of pasteurization and maintain the nutrients of strawberry drink. © 2018 Society of Chemical Industry.


Assuntos
Bactérias/isolamento & purificação , Manipulação de Alimentos/métodos , Fragaria/química , Sucos de Frutas e Vegetais/análise , Proteínas de Plantas/análise , Ultrassom/métodos , Antocianinas/análise , Antioxidantes/análise , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Hidrolases de Éster Carboxílico/análise , Catecol Oxidase/análise , Cor , Manipulação de Alimentos/instrumentação , Fragaria/enzimologia , Fragaria/microbiologia , Frutas/química , Frutas/crescimento & desenvolvimento , Sucos de Frutas e Vegetais/microbiologia , Viscosidade
18.
Food Res Int ; 99(Pt 1): 123-132, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28784468

RESUMO

Hyperbaric storage (HS) of raw watermelon juice, up to 10days at 50, 75, and 100MPa at variable/uncontrolled room temperature (18-23°C, RT) was studied and compared with storage at atmospheric pressure (AP) under refrigeration (4°C, RF) and RT, being evaluated microbiological (endogenous and inoculated), physicochemical parameters, and enzymatic activities. Ten days of storage at 50MPa resulted in a microbial growth evolution similar to RF, while at 75/100MPa were observed microbial load reductions on endogenous and inoculated microorganisms (Escherichia coli and Listeria innocua, whose counts were reduced to below the detection limit of 1.00 log CFU/mL), resulting in a shelf-life extension compared to RF. The physicochemical parameters remained stable at 75MPa when compared to the initial raw juice, except for browning degree that increased 1.72-fold, whilst at 100MPa were observed higher colour variations, attributed to a lycopene content decrease (25%), as well as reductions on peroxidase residual activity (16.8%) after 10days, while both polyphenol oxidase and pectin methylesterase residual activities were similar to RF. These outcomes hint HS as a reliable alternative to RF as a new food preservation methodology, allowing energy savings and shelf-life extension of food products. This is the first paper studying the effect of HS on inoculated microorganisms and on a broad number of physicochemical parameters and on endogenous enzymatic activities, for a preservation length surpassing the shelf-life by RF.


Assuntos
Citrullus , Temperatura Baixa , Enzimas/análise , Escherichia coli/crescimento & desenvolvimento , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Armazenamento de Alimentos/métodos , Sucos de Frutas e Vegetais/microbiologia , Oxigenoterapia Hiperbárica , Listeria/crescimento & desenvolvimento , Carga Bacteriana , Hidrolases de Éster Carboxílico/análise , Catecol Oxidase/análise , Peroxidase/análise , Fatores de Tempo
19.
Food Sci Technol Int ; 23(5): 385-395, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28675968

RESUMO

Browning is one of the main problems in senescence of mushrooms, and it is also one of the most important attributes accounting for the loss of the quality and reduction in market value. In order to study the relationship between the energy metabolism and the browning of white mushroom under high O2 dynamic-controlled atmosphere (HO-DCA), mushrooms were stored in 100% O2 (SCA1), 80% O2 + 20% CO2 (SCA2), 100% O2 for three days and then transferred into the treatment of 80% O2 + 20% CO2 (HO-DCA) at 2 ± 1 ℃ and air as control. In this study, adenosine triphosphate (ATP) content, energy charge level, sensory evaluation, browning of surface and flesh, cell membrane integrity, exogenous ATP, polyphenol oxidase (PPO) and peroxidase (POD) activity and genes encoding PPO of the white mushroom were investigated. These were all closely related to the browning of products. The optimal storage condition of the HO-DCA treatment could delay the browning of pericarp and flesh tissues of the mushrooms, inhibit PPO activity and reduce the relative expression levels of the three genes encoding PPO. Meanwhile, it maintained moderate POD activity, good sensory properties and cell membrane integrity in a certain extent and thus slowed down the senescence of mushrooms. Results indicated that there was a positive correlation between the ATP content and whitening index ( r = 0.901). In addition, HO-DCA maintained a higher ATP level, prolonged the storage time to 28 days and it might be an ideal strategy for preserving the quality of mushroom during storage.


Assuntos
Agaricus , Conservação de Alimentos/métodos , Oxigênio/fisiologia , Agaricus/química , Agaricus/efeitos dos fármacos , Agaricus/enzimologia , Catecol Oxidase/análise , Metabolismo Energético
20.
J Agric Food Chem ; 65(24): 5034-5040, 2017 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-28581737

RESUMO

The influence of growth regulator prohexadione-Ca (ProCa) concurrently with young canes removal on the modification of photosynthetic pigments content and antioxidant enzymes (peroxidase, POD; catalase, CAT; polyphenol oxidase, PPO; superoxide dismutase, SOD) activities in leaves and fruits of raspberry (Rubus idaeus L.) cultivar 'Willamette' was studied. ProCa increased while canes removal decreased chlorophylls and carotenoids content compared to control. POD, CAT, and PPO activities in leaves after removal of young canes were higher compared to control (2-4 times) which was visually confirmed for POD by isoelectrofocusing. Removal of young canes slithly increased, while ProCa significantly enhanced SOD activity in leaves compared to control (475.10 and 218.38 nkat mg-1 prot, respectively). Pattern of SOD activity in fruit was similar as in leaf with substantial increase compared to control (about 15 times). Combination of implemented measures increased activity of all enzymes in the leaves and fruits. Our study could provide a better knowledge of the ProCa and canes removal influences on the action of enzymes in order to regulate their activities in fruit products.


Assuntos
Ácidos Cetoglutáricos/farmacologia , Proteínas de Plantas/análise , Rubus/efeitos dos fármacos , Rubus/enzimologia , Catalase/análise , Catalase/metabolismo , Catecol Oxidase/análise , Catecol Oxidase/metabolismo , Frutas/química , Frutas/efeitos dos fármacos , Frutas/enzimologia , Frutas/crescimento & desenvolvimento , Peroxidases/análise , Peroxidases/metabolismo , Folhas de Planta/química , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Rubus/química , Rubus/crescimento & desenvolvimento , Superóxido Dismutase/análise , Superóxido Dismutase/metabolismo
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