Wild Strawberry Fruit Research Articles

Investigation of aroma components obtained by HS-SPME (Headspace-solid phase microextraction) method of wild strawberry (Fragaria vesca L.) and strawberry (Fragaria x ananassa Duch.) fruits

Wild strawberries (Fragaria vesca) are in the category of non-wood forest products due to their unique fragrance, aroma, and natural ability to grow. In this study, aroma components of wild strawberry (Fragaria vesca) and strawberry (Fragaria x ananassa) fruits were determined by Headspace-Solid Phase Micro-Extraction technique combined with Gas chromatography-mass spectrometry (HS-SPME/GC-MS). In addition, it aimed to compare the results of both fruits with each other by chemical classification of the aroma components determined from wild strawberry and strawberry fruits. As a result of the HS-SPME/GC-MS analysis; 50 and 76 aroma components were determined in wild strawberry and strawberry fruits, respectively. The structure of aroma components was defined as 97.63% of wild strawberries and 98.26% of strawberries. The main components in the aroma compounds are 2-undecanone (10.38%), γ-decalactone (8.81%), and eugenol (7.14%) in wild strawberry fruit; nerolidol (29.44%), γ-decalactone (26.36%) and bisabolol oxide II (4.23%) were found in strawberry fruits. In addition, chemical classes of identified aroma compounds were determined as ester, terpene or terpenoid, fatty acids, aldehyde, and ketone classes in Fragaria vesca and Fragaria x ananassa fruits. When the results are examined, it is seen that strawberry fruits are found to be higher than wild strawberry fruits in terms of percentage of aroma components, number of aroma components, and percentage of dominant components.

Comparison of red raspberry and wild strawberry fruits reveals mechanisms of fruit type specification.

Belonging to Rosaceae, red raspberry (Rubus idaeus) and wild strawberry (Fragaria vesca) are closely related species with distinct fruit types. While the numerous ovaries become the juicy drupelet fruits in raspberry, their strawberry counterparts become dry and tasteless achenes. In contrast, while the strawberry receptacle, the stem tip, enlarges to become a red fruit, the raspberry receptacle shrinks and dries. The distinct fruit-forming ability of homologous organs in these two species allows us to investigate fruit type determination. We assembled and annotated the genome of red raspberry (Rubus idaeus) and characterized its fruit development morphologically and physiologically. Subsequently, transcriptomes of dissected and staged raspberry fruit tissues were compared to those of strawberry from a prior study. Class B MADS box gene expression was negatively associated with fruit-forming ability, which suggested a conserved inhibitory role of class B heterodimers, PISTILLATA/TM6 or PISTILLATA/APETALA3, for fruit formation. Additionally, the inability of strawberry ovaries to develop into fruit flesh was associated with highly expressed lignification genes and extensive lignification of the ovary pericarp. Finally, co-expressed gene clusters preferentially expressed in the dry strawberry achenes were enriched in "cell wall biosynthesis" and "ABA signaling", while co-expressed clusters preferentially expressed in the fleshy raspberry drupelets were enriched in "protein translation". Our work provides extensive genomic resources as well as several potential mechanisms underlying fruit type specification. These findings provide the framework for understanding the evolution of different fruit types, a defining feature of angiosperms.

An Easy-to-Follow Pipeline for Long Noncoding RNA Identification: A Case Study in Diploid Strawberry Fragaria vesca.

Long noncoding RNAs (lncRNAs), defined as transcripts longer than 200 nucleotides without coding potential, are a new class of regulatory molecules with roles in diverse biological processes. New lncRNAs can readily be identified by mining RNA-seq data from a wide range of plant species. However, challenges remain as to how one can distinguish functional lncRNAs from mRNAs coding for small peptides or products of pseudogenes without any function. In this chapter, stepwise instruction is provided using RNA-seq datasets of developing wild strawberry fruit to illustrate each step. The workflow can be divided into three parts. Part I concerns standard RNA-seq data processing and analysis; part II describes lncRNA identification; part III describes several approaches aimed at shedding lights on lncRNA function. The description is intended for beginners with easy-to-follow steps. Text boxes provide codes and explanations. While it is relatively easy to identify lncRNAs, it is difficult to infer their function in the absence of coding information. Multiple RNA-seq libraries across tissues and stages are useful resources for deducing possible function of lncRNAs based on their expression and co-regulation.

Genetic diversity of strawberry germplasm using metabolomic biomarkers

High-throughput metabolomics technologies can provide the quantification of metabolites levels across various biological processes in different tissues, organs and species, allowing the identification of genes underpinning these complex traits. Information about changes of metabolites during strawberry development and ripening processes is key to aiding the development of new approaches to improve fruit attributes. We used network-based methods and multivariate statistical approaches to characterize and investigate variation in the primary and secondary metabolism of seven domesticated and seven wild strawberry fruit accessions at three different fruit development and ripening stages. Our results demonstrated that Fragaria sub-species can be identified solely based on the gathered metabolic profiles. We also showed that domesticated accessions displayed highly similar metabolic changes due to shared domestication history. Differences between domesticated and wild accessions were detected at the level of metabolite associations which served to rank metabolites whose regulation was mostly altered in the process of domestication. The discovery of comprehensive metabolic variation among strawberry accessions offers opportunities to probe into the genetic basis of variation, providing insights into the pathways to relate metabolic variation with important traits.

Genetic analysis of the wild strawberry (Fragaria vesca) volatile composition

The volatile composition of wild strawberry (Fragaria vesca) fruit differs from that of the cultivated strawberry, having more intense and fruity aromas. Over the last few years, the diploid F. vesca has been recognized as a model species for genetic studies of cultivated strawberry (F. x ananassa), and here a previously developed F. vesca/F. bucharica Near Isogenic Line collection (NIL) was used to explore genetic variability of fruit quality traits. Analysis of fruit volatiles by GC-MS in our NIL collection revealed a complex and highly variable profile. One hundred compounds were unequivocally identified, including esters, aldehydes, ketones, alcohols, terpenoids, furans and lactones. Those in a subset, named key volatile compounds (KVCs), are likely contributors to the special aroma/flavour of wild strawberry. Genetic analysis revealed 50 major quantitative trait loci (QTL) including 14 QTL for KVCs, and one segregating as a dominant monogenetic trait for nerolidol. The most determinant regions affecting QTLs for KVCs, were mapped on LG5 and LG7. New candidate genes for the volatile QTL are proposed, based on differences in gene expression between NILs containing specific fragments of F. bucharica and the F. vesca recurrent genome. A high percentage of these candidate genes/alleles were colocalized within the boundaries of introgressed regions that contain QTLs, appearing to affect volatile metabolite accumulation acting in cis. A NIL collection is a good tool for the genetic dissection of volatile accumulation in wild strawberry fruit and a source of information for genes and alleles which may enhance aroma in cultivated strawberry.

The Content of Secondary Metabolites and Antioxidant Activity of Wild Strawberry Fruit (Fragaria vesca L.).

Chemical analyses carried out in 2011–2013 aimed at evaluating the contents of flavonoids, free phenolic acids, tannins, anthocyanins, and antioxidant activity (%) by means of DPPH radical neutralization ability in fresh and air-dried fruits of three wild strawberry cultivars. Examinations revealed differences in contents of biologically active substances determined in raw versus dried material depending on the cultivar. Mean concentrations of flavonoids and tannins were highest in raw fruits of “Baron von Solemacher” cv., which amounted to 1.244 mg·g−1 and 6.09%, respectively. Fresh fruits of “Regina” cv. were characterized by the highest average content of phenolic acids and anthocyanins: 4.987 mg·g−1 and 0.636 mg·100 g−1. The pattern of mean contents of biologically active substances analyzed in air-dried fruits was similar. Significant differences in abilities to neutralize the DPPH radical to diphenylpicrylhydrazine by extracts made of examined wild strawberry fruits were also indicated.

Comparative analysis of secondary metabolites contents in Fragaria vesca L. fruits.

Fragaria vesca (wild strawberry) belongs to the Rosaceae family. Besides the leaves (Fragariae folium) and roots (Fragariae radix), the aromatic fruits (Fragariae fructus) of wild strawberry are also herbal materials used in medicine. The aim of this study was to compare the value of phytochemical and antioxidant activity of wild strawberry fruits (Fragaria vesca L.). The fruits were analyzed regarding their secondary metabolites contents (flavonoids, sum of phenolic acids, tannins, anthocyanins, DPPH), depending on the origin of the raw material (from natural habitats vs. cultivation). According to the obtained results, raw material originating from natural habitats contained significantly more flavonoids (0.559 mg∙g(-1)), compared to fruits harvested from cultivation (0.472 mg∙g(-1), on average). Mean concentration of phenolic acids ranged from 1.648 mg∙g(-1) - 2.348 mg∙g(-1), although the wild form was characterized by higher levels of examined substances. Tannins are an important fraction of phenolic compounds; their content in studied fruits ranged from 2.2% (from cultivation) - 3.0% (from natural habitats). When comparing the average contents of anthocyanins in the studied materials, it was revealed that remarkably more of these compounds were recorded in wild strawberry fruits harvested from natural habitats vs. those from cultivations: 132 mg∙100 g(-1) vs. 90 mg∙100 g(-1). A difference was indicated with respect to the ability of DPPH radical reduction to diphenylpicrylhydrazine by extracts made of examined fruits.

Antagonismo in vitro de aislados bacterianos de fresa comercial y silvestre vs. Botrytis cinerea y Rhizopus stolonifer

La fresa es una fruta no climatérica, con una vida postcosecha muy corta. La pérdida de calidad del fruto puede deberse, entre otros factores a daños ocasionados por fitopatógenos. Entre los más comunes se encuentran los hongos causantes del moho gris (Botrytis cinerea), y podredumbre blanca (Rhizopus stolonifer) dos fitopatógenos de gran impacto por su velocidad de crecimiento la cual les permite colonizar la superficie de los mismos ocasionado importantes pérdidas económicas. Una alternativa para el control de los daños por patógenos en frutos postcosecha es el uso de antagonistas microbianos que pueden estar presentes en la planta o el fruto pero en densidades bajas. En este estudio se aislaron bacterias de tejido foliar y frutos de fresa silvestre (Duchesnea indica Andr. Fock) y comercial. Se seleccionaron aquellos aislados que presentaron los mayores porcentajes de inhibición del crecimiento micelial de ambos fitopatógenos in vitro. Se aislaron un total de 32 cepas de las cuales 15 provinieron de fresa silvestre y 24 de fresa comercial. Se obtuvieron solo nueve cepas con potencial biocontrolador para uno o ambos patógenos. Los mayores porcentajes de inhibición del crecimiento micelial oscilaron entre 67.1% y 81.7% para Botrytis cinerea y 45.5% a 73.2% para Rhizopus stolonifer. Estos fueron obtenidos por cuatro aislados dos obtenidos de fresa silvestre y dos de comercial, todos ellos con capacidad para controlar a ambos fitopatógenos

Optimization of an active package for wild strawberries based on the release of 2-nonanone

Active packaging is becoming in an emerging food technology to improve quality and safety of food products, commonly based on the retention or release of compounds which are beneficial for the product. In this work, an active packaging system based on the release of 2-nonanone has been optimized to increase the postharvest shelf life of fresh wild strawberries during the marketing stage. To avoid that excessive levels of this volatile could affect the berries' taste and cause consumer rejection of the product, a preliminary sensory analysis was carried out to determine the threshold value of 2-nonanone, 7.16 mg/kg fresh wild strawberries. Taking this threshold value into account, diverse quantities of 2-nonanone were tested to optimize the packaging parameters. Wild strawberry fruits were packaged in the active packages developed and their quality monitored during storage at 10 °C with exposure to light to simulate real-life conditions on supermarket shelves. The analyses of weight loss, SSC, gas composition and aroma volatiles provide evidences that exposure to the highest-tested 2-nonanone concentrations are an effective way of maintaining the quality of wild strawberries during distribution and sale without modifying their typical taste.

Active Package for Wild Strawberry Fruit (Fragaria vescaL.)

An antimicrobial active package has been developed to improve the safety and quality of wild strawberries, as well as extending their shelf life. The fruits were packed in equilibrium-modified atmosphere packaging (EMAP), and the effect on Botrytis cinerea growth and on the quality parameters of the fruit by the addition of different amounts of 2-nonanone, an antifungal volatile compound naturally present in strawberries, was investigated during storage at 10 and 22 degrees C. The temperature of 10 degrees C was chosen as the temperature used at points of sale, and 22 degrees C was chosen as the control temperature. Fungal growth was inhibited in all cases, possibly due to the synergistic effect of high CO2 partial pressures and the presence of the antifungal compound. Weight, soluble solids, titrable acidity, and anthocyanin losses were retarded by the presence of 2-nonanone. This effect was more pronounced as the 2-nonanone concentration was increased at both temperatures. Therefore, an active package that releases 2-nonanone inhibits fungal decay and delays the senescence of highly perishable wild strawberry fruit.

Controlled Atmosphere Storage of Wild Strawberry Fruit (Fragaria vescaL.)

Controlled atmosphere storage technology to extend the shelf life of "Reina de los Valles" wild strawberry fruit (Fragaria vesca L.) was studied. Fruits were stored at 3 degrees C for three weeks in different atmosphere compositions: 0.05% CO2/21% O2 (air), 3% CO2/18% O2, 6% CO2/15% O2, 10% CO2/11% O2, and 15% CO2/6% O2. The effect of gas composition on soluble solids content, titrable acidity, pH, off-flavor, aroma volatiles, and consumer preference was monitored. The result showed that the 10% CO2/11% O2 combination can efficiently prolong the shelf life of wild strawberries by maintaining the quality parameters within acceptable values, through inhibiting the development of Botrytis cinerea, without significantly modifying consumer acceptance.