Volatile constituents and ellagic acid formation in strawberry fruits of selected cultivars

Phytochemical profile, enzyme inhibition, antioxidant, and antibacterial activity of Rosa pimpinellifolia L.: A comprehensive study to investigate the bioactivity of different parts (whole fruit, pulp, and seed part) of the fruit

The pharmaceutical and nutraceutical potentials of whole fruit, pulp and seeds of Rosa pimpinellifolia L. were evaluated. Forty-two phenolic compounds and two triterpenoids were identified in extracts by LC-MS/MS and GC-MS, respectively. The most prominent compounds were ellagic acid, catechin, epicatechin, tannic acid, quercetin, oleanolic acid, and ursolic acid. The highest enzyme inhibitory activities of the extracts (94.83%) were obtained against angiotensin-converting enzyme and were almost equal to those of the commercial standard (lisinopril, 98.99%). Whole fruit and pulp extracts (IC50:2.47 and 1.52 μg DW/mL) exhibited higher antioxidant capacity than the standards (α-tocopherol, IC50:9.89 μg DW/mL). The highest antibacterial activity was obtained against Bacillus cereus (MIC: 256 μg/mL) for the whole fruit extract. Correlation analyses were conducted to find the correlation between individual phenolics and enzyme inhibitory activities. The results showed the remarkable future of not only the edible part but also the seeds of black rose hips in phytochemical and functional aspects.

Nano-selenium repaired the damage caused by fungicides on strawberry flavor quality and antioxidant capacity by regulating ABA biosynthesis and ripening-related transcription factors

Recently, studies have shown that pesticides may have adverse effects on the flavor quality of the fruits, but there is still a lack of appropriate methods to repair the damage. This study investigated the effects and mechanism of applying the emerging material, nano‑selenium, and two fungicides (Boscalid and Pydiflumetofen) alone or together on the flavor quality and antioxidant capacity of strawberries. The results showed that the two fungicides had a negative impact on strawberry color, flavor, antioxidant capacity and different enzymatic systems. The color damage was mainly attributed to the impact on anthocyanin content. Nano‑selenium alleviated the quality losses by increasing sugar-acid ratio, volatiles, anthocyanin levels, enzyme activities and DPPH scavenging ability and reducing ROS levels. Results also showed that these damage and repair processes were related to the regulation of flavor and ripening related transcription factors (including FaRIF, FaSnRK1, FaMYB10, FaMYB1, FaSnRK2.6 and FaABI1), the upregulation of genes on sugar-acid, volatile, and anthocyanin synthesis pathways, as well as the increase of sucrose and ABA signaling molecules. In addition, the application of nano-Se supplemented the selenium content in fruits, and was harmless to human health. This information is crucial for revealing the mechanisms of flavor damage caused by pesticides to strawberry and the repaired of nano‑selenium, and broadens the researching and applying of nano‑selenium in repairing the damage caused by pesticides.

Geographical Indication Characteristics of Aroma and Phenolic Acids of the Changping Strawberry

Strawberry is the most consumed berry fruit worldwide due to its unique aroma and high nutritive value. This fruit is also an important source of phenolic compounds. Changping strawberries are recognized as a national agricultural product of geographical indication (GI) due to their unique flavor. Widely accepted standards for identifying GI strawberries from non-GI strawberries are currently unavailable. This study compared the aroma and phenolic acid composition of GI and non-GI strawberries. Furthermore, the characteristic aroma and phenolic acid markers of GI strawberries were determined. A classification model based on the markers was established using Fisher discriminant analysis (FDA). In this study, six groups of strawberries with variety name of "Hongyan", including GI strawberries from Changping and non-GI strawberries from Changping, Miyun, Pinggu, Shunyi, and Tongzhou, were collected. A total of 147 volatile substances were discovered using gas chromatography-tandem mass spectrometry. The contents of a few compounds principally responsible for the distinctive aroma in GI strawberries were in the top three of the six groups, providing GI strawberries with a generally pleasant fragrance. OPLS-DA identified isoamyl butyrate and trans-2-octen-1-ol as characteristic markers. Enrichment analysis indicated that beta-oxidation of very long-chain fatty acids, mitochondrial beta-oxidation of very long-chain fatty acids, fatty acid biosynthesis, and butyrate metabolism played critical roles in volatile compound biosynthesis. The total phenolic content was 24.41-36.46 mg/kg of fresh weight. OPLS-DA results revealed that cinnamic acid could be used as a characteristic phenolic acid marker of GI strawberries. Based on the three characteristic markers, FDA was performed on the different groups, which were then divided. The separation of strawberry samples from different origins using the three characteristic markers was found to be feasible. These findings help effectively understand the aroma and phenolic acid composition of strawberries and contribute to the development of strawberries with a pleasant fragrance and health benefits.

Transcriptomics Reveals the Mechanism of Rosa roxburghii Tratt Ellagitannin in Improving Hepatic Lipid Metabolism Disorder in db/db Mice

A complex metabolic disorder, type 2 diabetes, was investigated to explore the impact of ellagitannin, derived from Rosa roxburghii Tratt (RTT), on liver lipid metabolism disorders in db/db mice. The findings demonstrated that both RTT ellagitannin (C1) and RTT ellagic acid (C4) considerably decelerated body mass gain in db/db mice, significantly decreased fasting blood glucose (FBG) levels, and mitigated the aggregation of hepatic lipid droplets. At LDL-C levels, C1 performed substantially better than the C4 group, exhibiting no significant difference compared to the P (positive control) group. An RNA-seq analysis further disclosed that 1245 differentially expressed genes were identified in the livers of experimental mice following the C1 intervention. The GO and KEGG enrichment analysis revealed that, under ellagitannin intervention, numerous differentially expressed genes were significantly enriched in fatty acid metabolic processes, the PPAR signaling pathway, fatty acid degradation, fatty acid synthesis, and other lipid metabolism-related pathways. The qRT-PCR and Western blot analysis results indicated that RTT ellagitannin notably upregulated the gene and protein expression levels of peroxisome proliferator-activated receptor alpha (PPARα) and peroxisome proliferator-activated receptor gamma (PPARγ). In contrast, it downregulated the gene and protein expression levels of sterol regulatory element-binding protein (SREBP), recombinant fatty acid synthase (FASN), and acetyl-CoA carboxylase (ACC). Therefore, RTT ellagitannin can activate the PPAR signaling pathway, inhibit fatty acid uptake and de novo synthesis, and ameliorate hepatic lipid metabolism disorder in db/db mice, thus potentially aiding in maintaining lipid homeostasis in type 2 diabetes.

Physicochemical Quality, Polyphenol Profiles, and Postharvest Performance of Florida Pearl® 'FL 16.78-109' White Strawberries Compared to the Red Cultivar 'Florida Brilliance'

White-fruited strawberry cultivars have recently become popular due to their exotic appearance and flavor, but more needs to be known about their overall quality and postharvest performance. The objective of this study was to characterize and compare the overall quality of the white-fruited strawberry Florida Pearl® 'FL 16.78-109' against the commercial, red-fruited strawberry 'Florida Brilliance' at harvest and during cold storage (1 °C). Results showed that harvest date and weather conditions contributed to significant differences in fruit quality, regardless of the cultivar. However, Pearl was softer at harvest and had lower total phenolic and anthocyanin contents but was less acidic and had higher total sugars and ascorbic acid contents than Brilliance. Pearl major polyphenols were kaempferol 3-glucoside, quercetin 3-glucoside, quercetin, and gallic acid, while for Brilliance epicatechin, pelargonidin, pelargonidin 3-glucoside, and ferulic acid were the major polyphenol compounds identified. After cold storage, Pearl lost less weight than Brilliance and showed a less dramatic decline in individual polyphenols. Pearl and Brilliance anthocyanins and phenolic acids were the polyphenol groups most affected by cold storage because they showed the highest decline from harvest to the end of storage. Cold storage also had different effects on other polyphenols, but the effect was cultivar-dependent. Overall, white strawberries have a unique appearance, are sweet, have an excellent bioactive profile, and can maintain good postharvest quality.

The Effect of Imidacloprid on the Volatile Organic Compound Profile of Strawberries: New Insights from Flavoromics

Organic agriculture is of great socioeconomic significance because it can promote the nutritional quality of horticultural crops and is environmentally friendly. However, owing to the lack of techniques for studying complex aroma-related chemical profiles, limited information is available on the influence of organic practices on the flavor quality of strawberries, one of the primary factors driving consumer preferences. Here, two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GC×GC-TOF-MS) and flavoromics analysis was employed to investigate the profiles and differences in the volatile organic compounds (VOCs) of strawberries under organic (without imidacloprid) and conventional (with imidacloprid) agricultural practices. A total of 1164 VOCs, representing 23 chemical classes (e.g., aldehydes, terpenes, and furanone compounds), were detected, which is the highest number of VOCs that have ever been detected in strawberries. The sensory evaluation results indicated that there was a notable influence of imidacloprid (IMI) on the aroma of the strawberries. Principal component analysis and partial least squares discriminant analysis results suggested that the composition of volatile compounds significantly differed in the present study between the IMI-treated and non-IMI-treated groups. Furthermore, the flavor-related indicators of 25 key contributors to the differences between the two treatment groups suggested that VOC profiles can be considered an indicator for distinguishing between strawberries from different agricultural practices. Flavoromics can provide new insights into the quality of strawberries from different agricultural practices.

Selective determination of ellagic acid in aqueous solution using blue-green emissive copper nanoclusters

Development of beneficial sensors to analyze ellagic acid concentrations is of great importance for food safety and human health. Herein, a facile and fast fluorescent probe was carried out for the excellently selective and sensitive measurement of ellagic acid in real samples through histidine protected copper nanoclusters (histidine@Cu NCs) as a nanosensor. This as-developed histidine@Cu NCs were performed through UV-vis absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy and fluorescence lifetime analysis. The TEM image revealed that this nanomaterial had spherical features with the average diameter of 2.5 ± 0.05 nm. The blue-green fluorescence of this Cu NCs was found under the UV light. Meanwhile, the maximum excitation and emission wavelength were located at 387 nm and 488 nm. After addition of ellagic acid, the fluorescence of histidine@Cu NCs was slowly weakened with excellent linear range of 0.5-300 μM and detection limit of 0.077 μM. The fluorescence weakening mechanism of this nanosensor were attributed to the inner filter effect (IFE) and static quenching. Finally, this as-established analysis platform was successfully employed to measure ellagic acid in real samples.

Rapid and Non-Destructive Techniques for the Discrimination of Ripening Stages in Candonga Strawberries

Electronic nose (e-nose), attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy and image analysis (IA) were used to discriminate the ripening stage (half-red or red) of strawberries (cv Sabrosa, commercially named Candonga), harvested at three different times (H1, H2 and H3). Principal component analysis (PCA) performed on the e-nose, ATR-FTIR and IA data allowed us to clearly discriminate samples based on the ripening stage, as in the score space they clustered in distinct regions of the plot. Moreover, a correlation analysis between the e-nose sensor and 57 volatile organic compounds (VOCs), which were overall detected in all the investigated fruit samples by headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry (HS-SPME/GC-MS), allowed us to distinguish half-red and red strawberries, as the e-nose sensors gave distinct responses to samples with different flavours. Three suitable broad bands were individuated by PCA in the ATR-FTIR spectra to discriminate half-red and red samples: the band centred at 3295 cm⁻¹ is generated by compounds that decline, whereas those at 1717 cm⁻¹ and at 1026 cm⁻¹ stem from compounds that accumulate during ripening. Among the chemical parameters (titratable acidity, total phenols, antioxidant activity and total soluble solid) assayed in this study, only titratable acidity was somehow correlated to ATR-FTIR and IA patterns. Thus, ATR-FTIR spectroscopy and IA might be exploited to rapidly assess titratable acidity, which is an objective indicator of the ripening stage.

Impact of UHT processing on volatile components and chemical composition of sea buckthorn (Hippophae rhamnoides) pulp: A prediction of the biochemical pathway underlying aroma compound formation

The effects of ultrahigh-temperature sterilization (UHT) on the volatile components and chemical composition of sea buckthorn pulp (SBP) were evaluated firstly. UHT had significant effects on the volatiles of SBP (mainly occurring at 140 °C for 2 s and 4 s), in which 140 °C for 2 s resulted in a decrease of 3.48% and 14.60% in total volatiles and esters, and an increase of 6.73% in alcohols, while alcohols contents sharply decreased by 6.90% at 140 °C for 4 s. Moreover, 140 °C for 2 s and 4 s decreased the amino acid content by 35.39% and 29.75%, respectively, while UHT significantly promoted the increase of fatty acids, but only a small increase at 140 °C for 4 s. The speculation is that a large number of volatiles were formed during the 140 °C for 2 s and 4 s, mainly from amino acid reactions and lipid oxidation.

Patterns of Volatile Diversity Yield Insights Into the Genetics and Biochemistry of the Date Palm Fruit Volatilome

Volatile organic compounds are key components of the fruit metabolome that contribute to traits such as aroma and taste. Here we report on the diversity of 90 flavor-related fruit traits in date palms (Phoenix dactylifera L.) including 80 volatile organic compounds, which collectively represent the fruit volatilome, as well as 6 organic acids, and 4 sugars in tree-ripened fruits. We characterize these traits in 148 date palms representing 135 varieties using headspace solid-phase microextraction gas chromatography. We discovered new volatile compounds unknown in date palm including 2-methoxy-4-vinylphenol, an attractant of the red palm weevil (Rhynchophorus ferrugineus Olivier), a key pest that threatens the date palm crop. Associations between volatile composition and sugar and moisture content suggest that differences among fruits in these traits may be characterized by system-wide differences in fruit metabolism. Correlations between volatiles indicate medium chain and long chain fatty acid ester volatiles are regulated independently, possibly reflecting differences in the biochemistry of fatty acid precursors. Finally, we took advantage of date palm clones in our analysis to estimate broad-sense heritabilities of volatiles and demonstrate that at least some of volatile diversity has a genetic basis.

Profiles of Volatile and Phenolic Compounds as Markers of Ripening Stage in Candonga Strawberries

Volatile compounds, quality traits (total phenols and antioxidant capacity) and High-performance liquid chromatography (HPLC)-isolated polyphenols of strawberries, variety Sabrosa, commercially referred to as “Candonga”, harvested at three different times (H1, H2 and H3) and at two different ripening stages, namely half-red (Half-red-H1, Half-red-H2 and Half-red-H3) and red (Red-H1, Red-H2 and Red-H3) were evaluated. Dominant anthocyanins, namely cyanidin-3-O-glucoside, pelargonidin-3-O-glucoside and pelargonidin-3-O-rutinoside, as well as p-coumaryl hexoside increased during harvesting, differently from flavonoids, such as quercetin-3-O-glucoside, kaempferol-3-O-glucoronide and quercetin 3-O-glucoronide, that declined. Samples clustered in different quadrants of the principal component analysis (PCA) performed on volatiles, quality traits and phenolic compounds, highlighting that only the red samples were directly correlated to volatile components, as volatiles clearly increased both in number and amount during ripening. In particular, volatiles with a positive impact on the consumers’ acceptance, including butyl butyrate, ethyl hexanoate, hexyl acetate, nonanal, terpenes and lactones, were positively associated with the Red-H1 and Red-H2 strawberries, while volatiles with negative coefficients related to consumer liking, including isopropyl butyrate, isoamyl butyrate and mesifurane directly correlated with the Red-H3 samples. Accordingly, strawberries harvested at Red-H1 and Red-H2 ripening stages could be preferred by the consumers compared to the Red-H3 fruit. Altogether, these results could help to individuate quality traits as putative markers of the ripening stage, and optimize the process of post-harvesting ripening to preserve or improve the desirable aromatic characteristics of strawberries.