Optimization of harvest date according to the volatile composition of Mediterranean aromatic herbs at different vegetative stages

Most of the studies concerning the optimal harvest date of aromatic herbs have dealt with different parts of plant such as flowers, leaves, stems, roots and seeds, but none have evaluated the effect of different harvest date at different vegetative stages on shoots (leaves and stems). Therefore, the main objective was to investigate the effects of harvest date of two consecutive seasons on the volatile composition of shoots of 4 aromatic herbs (dill, parsley, coriander and mint) widely cultivated worldwide. The impact of harvest date during the evolution of vegetative part of four aromatic herbs (parsley, dill, coriander and mint) was investigated. Volatile compounds of shoots of the four herbs were identified by GC–MS. The main compounds were 1,3,8-p-menthatriene, betaphellandrene, myristicin and myrcene for parsley, alpha-phellandrene, dillether and beta-phellandrene for dill, decanal, E-2-dodecenal, 1-decanol and dodecanal for coriander, and carvone and limonene in case of mint. There was a significant effect of harvest date on the content of volatile compounds of the four species. The results showed that highest total concentration of volatiles and therefore the optimal harvest date of parsley was found 9 weeks after planting date with a total concentration of 2543 mg kg−1, for dill was 2619 mg kg−1 14 weeks after planting date, for coriander was 2191 mg kg−1 3 weeks after planting date, and 23329 mg kg−1 for mint 6 weeks after planting dat

Hygienic quality of dehydrated aromatic herbs marketed in Southern Portugal

Dehydrated aromatic herbs are highly valued ingredients, widely used at home level and by food processing industry, frequently added to a great number of recipes in the Mediterranean countries. Despite being considered low-moisture products and classified as GRAS, during pre and post-harvesting stages of production they are susceptible of microbial contamination. In Europe an increasing number of food recalls and disease outbreaks associated with dehydrated herbs have been reported in recent years. In this study the microbial quality of 99 samples of aromatic herbs (bay leaves, basil, coriander, oregano, parsley, Provence herbs, rosemary and thyme) collected from retails shops in the region of Algarve (Southern Portugal) was assessed. All the samples were tested by conventional methods and were assayed for the total count of aerobic mesophilic microorganisms, Salmonella spp., Escherichia coli, coagulase-positive staphylococci and filamentous fungi. Almost 50 % of the herbs did not exceed the aerobic mesophilic level of 104 CFU/g. The fungi count regarded as unacceptable (106 CFU/g) was not found in any of the tested herbs, while 84 % of the samples ranged from ≤102 to 104 CFU/g. No sample was positive for the presence of Salmonella spp., Escherichia coli and staphylococci. The results are in compliance with the European Commission criteria although they point out to the permanent need of surveillance on the good standards of handling/cooking practices as well as the importance of avoiding contamination at production, retailing and distribution. The microbiological hazards associated with the pathogenic and toxigenic microbiota of dried herbs remain as a relevant public health issue, due to the fact that they are added to foods not submitted to any following lethal procedure. Control measures should be adopted in order to ensure that all phases of their supply chain respect the food safety standards.FCT: UID/BIA/04325/2019.info:eu-repo/semantics/publishedVersio

Effects of irrigation dose, plant density, application of organic acids, and harvest date on the quality and yield of commercial aromatic plants

Programa de Doctorado en Recursos y Tecnologías Agrarias, Agroambientales y AlimentariasNowadays, optimizing agronomical factors becomes very important to produce crops with both high production and quality. The optimization of several agricultural practices was the main purpose of this PhD dissertation. To reach this aim, the analysis of the volatile composition of different herbs was carried out to investigate the influence of (i) harvest date, (ii) irrigation dose, and (iii) plant density on the commercial yield and plant quality. Four herbs were studied: (i) dill (Anethum graveolens), (ii) parsley (Petroselinum crispum), (iii) coriander (Coriandrum sativum), (iv) and mint (Mentha piperita). Hydrodistllation, using a Deryng apparatus, to extract the herbs essential oils or volatile fractions, while gas chromatography with a mass spectrometry detector (GC-MS) was used to isolate and identify the volatile compounds; finally, the quantification was done by using gas chromatography with a flame ionization detector (GC-FID). Results showed that the predominant compounds of the volatile fractions of the aerial parts of: (i) dill were α-phellandrene, dill ether, and β-phellandrene, (ii) parsley were 1,3,8-p-menthatriene and β-phellandrene, (iii) coriander were E-2-dodecenal, dodecanal, and octane, and (iv) mint were carvone and limonene. All data generated in the current dissertation (e.g. total yield, volatile composition, and descriptive sensory profile) were used to provide a final recommendation about the optimal harvest date, irrigation dose, and plant density for each of the above mentioned aromatic herbs. The commercial production (total yield), composition of the volatile fraction, and sensory quality of dill, parsley, coriander, and mint were significantly affected by harvest date, irrigation dose, and plant density. Data obtained in the current study showed that the optimal harvest date were: for dill the second commercial harvest (approximately the 4th week of February), for parsley the first commercial harvest (approximately the 3rd week of November), for coriander the second commercial harvest (approximately the 1st week of February), and for mint the first commercial harvest (approximately the 2nd week of December). The application of the irrigation dose 2180 m3/ha and the plant density 7.41 plant/m2 led to the highest aromatic and sensory quality of the dill plants; while, to produce dill plants with the highest yield, 1585 m3/ha and 5.56 plant/m2 must be applied. In a similar way, the use of 861 m3/ha and 5.56 plant/m2 led to the highest yield and quality of parsley plants. On the other hand, the effect of a preharvest treatment with malic acid, oxalic acid, and acetylsalicylic acid at 3 concentrations (1, 2, and 3 mM) on phenolic composition and antioxidant capacity of dill, parsley and coriander was also investigated. The results showed the presence of 30 phenolic compounds in dill, parsley, and coriander extracts. The major phenolic compounds found were (i) dill: neochlorogenic acid and quercetin glucuronide, (ii) parsley: apigenin-7- apiosylglucoside (apiin) and isorhamnetin-3-O-hexoside, and (iii) coriander: dimethoxycinnamoyl hexoside and quercetin-3-O-rutinoside. In fact, the preharvest treatment of both dill and parsley with organic acids did not significantly improve the quality of these herbs; however, experimental results proved that coriander shoots treated by a preharvest treatment with these organic acids had a significant enhancement of both the concentration of phenolic compounds and the antioxidant capacity.Actualmente, la optimización de las prácticas agronómicas, es de gran importancia para la obtención de cultivos de elevada producción y calidad. Esta optimización de diversas prácticas culturales, es el principal propósito de esta Tesis Doctoral. Para alcanzar este propósito, se ha realizado el análisis de los compuestos volátiles y la producción con el objetivo de investigar la influencia de la (i) fecha de recolección, (ii) la dosis de riego y (iii) la densidad de plantación sobre la producción calidad de eneldo (Anethum graveolens), perejil (Petroselinum crispum), cilantro (Coriandrum sativum) y menta (Mentha piperita). La hidrodestilación, con el aparato Deryng, se empleó para la extracción de los aceites esenciales o las fracciones volátiles, mientras que, para la separación e identificación de los compuestos volátiles, se empleó la cromatografía de gases con detector de espectrometría de masas; finalmente, la cuantificación se realizó mediante cromatografía de gases con detector de ionización de llama. Los resultados mostraron que los principales compuestos volátiles fueron (i) en eneldo α-felandreno, éter de eneldo y β-felandreno, (ii) en perejil, 1,3,8-p-mentatrieno y β-felandreno, (iii) en cilantro, E-2-dodecenal, dodecanal y octano, y (iv) en menta, carvona y limoneno. Los datos generados en esta Tesis Doctoral (por ejemplo, producción, concentración de compuestos volátiles y análisis sensorial descriptivo), se emplearon para alcanzar la decisión sobre la estimación de la fecha óptima de recolección, dosis de riego y la densidad de plantación. Todos los parámetros estudiados, se vieron afectados por la fecha de recolección, la dosis de riego y la densidad de plantación. Los datos obtenidos, revelaron que la fecha óptima de recolección de eneldo fue en el segundo corte (última semana de febrero), para perejil, en el primer corte (tercera semana de noviembre), para cilantro fue el segundo corte (primera semana de febrero) y para menta, el primer corte (segunda semana de diciembre). La aplicación de una dosis de riego de 2180 m3/ha y densidad de plantación 7.41 plantas/m2, condujo a la obtención de eneldo de elevada calidad aromática y sensorial; mientras que para obtener una elevada producción se requirieron 1585 m3/ha y 5.56 plantas/m2. En lo que respecta al perejil, una dosis de riego de 861 m3/ha y densidad de plantación 5.56 plantas/m2 condujeron a una gran producción y elevada calidad. Además, se investigó el efecto de un tratamiento pre-cosecha con ácido málico, oxálico y acetil salicílico a 3 concentraciones (1, 2, y 3 mM) sobre la concentración de compuestos fenólicos y la capacidad antioxidante de eneldo, perejil y cilantro. Los resultados, indicaron la presencia de 30 compuestos fenólicos, siendo los más importantes en (i) eneldo: ácido neoclorgénico y quercetina glucorónido, (ii) en perejil: 7-apiosilglucósidos de apigenina y isoramnetina-3-O-hexosido, y (iii) en cilantro: quercetina-3-O-rutinósido. De hecho, el tratamiento pre-cosecha de eneldo y perejil, no mejoró de manera significativa la calidad de dichas hierbas aromáticas; mientras que, los resultados, mostraron que el cilantro tratado con estos ácidos orgánicos, tuvo una mejora significativa tanto en la concentración de compuestos fenólicos, como en la capacidad antioxidante

Volatile Composition of Essential Oils from Different Aromatic Herbs Grown in Mediterranean Regions of Spain

Volatile composition of essential oils from dill, parsley, coriander, and mint were investigated at different harvest dates to determine the most suitable harvest time for each these herbs. Hydrodistillation (HD), using a Deryng system, was used for isolating the essential oils. Isolation and identification of the volatile compounds were performed using gas chromatography-mass spectrometry (GC-MS) instrument. The results of gas chromatography-flame ionization detector (GC-FID) analysis (quantification) showed that the main components in the essential oil of dill shoots were α-phellandrene, dill ether, and β-phellandrene, and the optimal harvest date was D2 (second harvest, fourth week of February 2015). For parsley shoots, the main compounds were 1,3,8-p-menthatriene, β-phellandrene, and P1 (first harvest, third week of November 2014) was the sample with the highest essential oil. For coriander, the main compounds were E-2-dodecenal, dodecanal, and octane and the highest contents were found at C2 (second harvest, 5 February 2015); while, the main two components of mint essential oil were carvone and limonene, and the highest contents were found at M1 (first harvest, second week of December 2014). The present study was the first one reporting data on descriptive sensory analysis of aromatic herbs at this optimal harvest date according to the content of volatile compounds of their essential oils

Effects of irrigation dose, plant density, application of organic acids, and harvest date on the quality and yield of commercial aromatic plants

Actualmente, la optimización de las prácticas agronómicas, es de gran importancia para la obtención de cultivos de elevada producción y calidad. Esta optimización de diversas prácticas culturales, es el principal propósito de esta Tesis Doctoral. Para alcanzar este propósito, se ha realizado el análisis de los compuestos volátiles y la producción con el objetivo de investigar la influencia de la (i) fecha de recolección, (ii) la dosis de riego y (iii) la densidad de plantación sobre la producción calidad de eneldo (Anethum graveolens), perejil (Petroselinum crispum), cilantro (Coriandrum sativum) y menta (Mentha piperita)Nowadays, optimizing agronomical factors becomes very important to produce crops with both high production and quality. The optimization of several agricultural practices was the main purpose of this PhD dissertation. To reach this aim, the analysis of the volatile composition of different herbs was carried out to investigate the influence of (i) harvest date, (ii) irrigation dose, and (iii) plant density on the commercial yield and plant quality. Four herbs were studied: (i) dill (Anethum graveolens), (ii) parsley (Petroselinum crispum), (iii) coriander (Coriandrum sativum), (iv) and mint (Mentha piperit

Volatile Composition of Essential Oils from Different Aromatic Herbs Grown in Mediterranean Regions of Spain

Volatile composition of essential oils from dill, parsley, coriander, and mint were investigated at different harvest dates to determine the most suitable harvest time for each these herbs. Hydrodistillation (HD), using a Deryng system, was used for isolating the essential oils. Isolation and identification of the volatile compounds were performed using gas chromatography-mass spectrometry (GC-MS) instrument. The results of gas chromatography-flame ionization detector (GC-FID) analysis (quantification) showed that the main components in the essential oil of dill shoots were α-phellandrene, dill ether, and β-phellandrene, and the optimal harvest date was D2 (second harvest, fourth week of February 2015). For parsley shoots, the main compounds were 1,3,8-p-menthatriene, β-phellandrene, and P1 (first harvest, third week of November 2014) was the sample with the highest essential oil. For coriander, the main compounds were E-2-dodecenal, dodecanal, and octane and the highest contents were found at C2 (second harvest, 5 February 2015); while, the main two components of mint essential oil were carvone and limonene, and the highest contents were found at M1 (first harvest, second week of December 2014). The present study was the first one reporting data on descriptive sensory analysis of aromatic herbs at this optimal harvest date according to the content of volatile compounds of their essential oils

Volatile Composition of Smoked and Non-Smoked Iranian Rice

In this work, the volatile profiles of smoked and non-smoked Iranian rice were identified, and their relative abundance was calculated and compared. Headspace solid-phase microextraction together with gas chromatography-mass spectrometry (SPME-GC-MS) were used to extract and identify the volatile compounds. The main groups of volatiles in Iranian rice were aldehydes, ketones, phenol derivatives, furans, linear hydrocarbons, esters and terpenes. The chemical family aldehydes was the most abundant one in the profile of non-smoked rice, while phenol derivatives and furans predominated in smoked samples. This study is the first one reporting comparative data of volatile compounds between smoked and non-smoked Iranian rice