Consuming Blackberry as a Traditional Nutraceutical Resource from an Area with High Anthropogenic Impact

Heavy metal contamination (Cu, Pb, and Cd) of washed and unwashed roadside blackberries (Rubus fruticose L.)

Foraging provides a multitude of individual, social, and environmental benefits. With green spaces decreasing in the United Kingdom, there is an opportunity for roadside verges to become valuable foraging resources; however, there is public concern over the safety of roadside forage. Human ingestion of heavy metal contaminants, such as copper (Cu), lead (Pb), and cadmium (Cd), originating from traffic activity, induces toxic effects in the body. Therefore, maximum Cu, Pb, and Cd guideline limits for human consumption in small fruits were established. However, studies of heavy metal concentrations in roadside forage and the effects of surface washing on concentrations are limited. This study examined Cu, Pb, and Cd in washed and unwashed wild blackberries (Rubus fruticose L.) along a main road in Kent, UK, and compares the values with maximum guideline limits. In all 44 samples, Cu, Pb and Cd concentrations were well below the maximum guideline limit or daily reference intake (RI) value. Cu and Pb concentrations were below the maximum daily intake in every sample if foragers eat one portion (80 g) of berries a day, but consuming a larger quantity of berries per day (e.g., 1 kg) could lead to an intake above the guideline limit for Cu (1 mg) and Pb (0.1 mg), but not Cd (0.03 mg). Washing did not significantly reduce the concentrations of Cu (p = 0.174) or Cd (p = 0.752) in blackberries, but did significantly reduce the Pb concentration (p < 0.001). However, Pb concentration was below maximum guideline limits for every sample regardless of washing treatment. Thus, wild blackberries collected from the roadside were suitable for human consumption, although the findings are not representative of all foraged berries or road networks. Integr Environ Assess Manag 2024;00:1-9. © 2024 The Author(s). Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Trends in maintaining postharvest freshness and quality of Rubus berries

Blackberries and raspberries, commonly known as Rubus berries, are commercially grown worldwide across different climates. Rubus berries contain wide array of phytochemicals, vitamins, dietary fibers, minerals, and unsaturated fatty acids. Nevertheless, these berries have short storage life which is the major constraint in their supply chains leading to higher postharvest losses. Inappropriate harvest handling, physical bruising, insect pests, and postharvest diseases lower the acceptability of fruit among consumers and other supply chain stakeholders. Additionally, the susceptibility to microbial decay, fruit softening, higher ethylene production, respiratory activity, and increased oxidation of anthocyanins, phenolics, and flavonoids considerably affects the marketability of Rubus berries at domestic and international markets. To date, several postharvest strategies such as cold storage, precooling, modified and controlled atmospheres, anti-ripening chemicals, edible coatings, biological agents, and nonchemical alternatives (heat treatment, ultrasound, irradiations, ozone) have been reported to prolong storage life, ensure food safety, and maintain the nutritional quality of Rubus berries. This review briefly encompasses multiple aspects including harvest maturity indices, regulation of fruit ripening, pre and postharvest factors affecting fruit quality, and an update on postharvest quality preservation by employing postharvest technologies to extend the storage life and maintaining the bioactive compounds in Rubus berries which are lacking in the literature. Accordingly, this review provides valuable information to the industry stakeholders and scientists offering relevant solutions, limitations in the application of certain technologies at commercial scale, highlighting research gaps, and paving the way forward for future investigations.

Fruits as nutraceuticals: A review of the main fruits included in nutraceutical patents

Fruits have relevant usefulness in the elaboration of nutraceutical compositions and, as it is considered a "natural medicine", its market has been growing exponentially each year. Fruits, in general, contain a large source of phytochemicals, carbohydrates, vitamins, amino acids, peptides and antioxidants that are of interest to be prepared as nutraceuticals. The biological properties of its nutraceuticals can range from antioxidant, antidiabetic, antihypertensive, anti-Alzheimer, antiproliferative, antimicrobial, antibacterial, anti-inflammatory, among others. Furthermore, the need for innovative extraction methods and products reveals the importance of developing new nutraceutical compositions. This review was developed by searching patents of nutraceuticals from January 2015 until January 2022 in Espacenet, the search database of the European Patent Office (EPO). Of 215 patents related to nutraceuticals, 43% (92 patents) were including fruits, mainly berries. A great number of patents were focused on the treatment of metabolic diseases, representing 45% of the total patents. The principal patent applicant was the United States of America (US), with 52%. The patents were applied by researchers, industries, research centers and institutes. It is important to highlight that from 92 fruit nutraceutical patent applications reviewed, 13 already have their products available on the market.

Biologically Active Preparations from the Leaves of Wild Plant Species of the Genus Rubus

The plants of the genus Rubus (R.) are applied as antiseptic agents in the treatment of skin diseases. Despite the great interest in plants of this genus, there are few reports on the antioxidant and biological activities of preparations obtained from the leaves of these plants. Therefore, we decided to evaluate the antioxidant activity of preparations from leaves of wild plant species of the genus Rubus using the frequently applied DPPH, ABTS, and FRAP methods, as well as to determine the total polyphenol content using the Folin−Ciocalteau method and perform qualitative evaluation by gas chromatography−mass spectrometry (GC-MS). The bactericidal and fungicidal activities of the obtained preparations were evaluated by applying laboratory tests: using the disc and the well methods based on the standards EN 13697:2019, EN 13697:2015, and EN 1500:2013. Microbiological tests of the plant preparations against bacteria, fungi, and yeasts isolated from the environment and against reference strains were performed. Moreover, antimicrobial testing of antibiotics against the tested strains was performed for comparison. The n-octanol/water partition coefficient of the obtained preparations was determined by the shake-flask method to determine their lipophilicity. According to the results, a high content of polyphenols and other antioxidant and biologically active compounds can be thought of as the parameter responsible for the effective activity of plant preparations obtained from wild plant species of the genus Rubus. The methods for determining bactericidal and fungicidal activity clearly demonstrates that preparations with reduced ethanol content exhibit bactericidal and fungicidal activity on surfaces. Testing of hand disinfection by means of rubbing with the preparations confirmed their antimicrobial activity against Escherichia coli K12 NCTC 10538. The obtained results show that the tested preparations exhibit on average two times lower activity against the reference bacterial strains than comparable antibiotics. The preparations obtained from the leaves of R. idaeus L. and R. fruticosus L. could complement classical antibiotics. While environmental bacteria showed a similar response to the preparations and antibiotics, their sensitivity was about one-third less than that of the reference strains. Our studies have shown that the obtained preparations are highly hydrophilic (logP < 0). Thus, these preparations can only be used in lipid bilayers in the aqueous core of liposomes, not in the lipid envelope.

Small RNA and degradome sequencing reveal the role of blackberry miRNAs in flavonoid and anthocyanin synthesis during fruit ripening

Blackberry shrubs are economically important for their production of small, pulped fruits. This species has attracted much attention because of the unique flavor of its fruits and their rich nutritional and medicinal value. In this study, microRNAs (miRNAs) and their target genes related to flavonoids and anthocyanins in blackberry fruits during ripening were analyzed and identified by small RNA and degradome sequencing technology, and the expression levels of key miRNAs in unripe and ripe blackberry fruits were verified via the RT-qPCR. A total of 258 known miRNAs were identified. Eighty differentially expressed miRNAs (DEMs) were detected in the fruits of the ripe group compared with those of the unripe group. Differentially expressed miR828-x/miR828-z and unigene0086056 (unknown function) were coexpressed. Moreover, miR858 had the most target genes for the synthesis of flavonoids and anthocyanins. Taken together, these results provide important value for improving the quality of blackberry fruits and breeding blackberry plants that produce high-flavonoid fruits for the pharmaceutical industry.

Heavy metal concentrations in floodplain soils of the Innerste River and in leaves of wild blackberries (Rubus fruticosus L. agg.) growing within and outside the floodplain: the legacy of historical mining activities in the Harz Mountains (Germany)

We studied heavy metal levels in floodplain soils of the Innerste River in northern Germany and in the leaves of wild blackberries (Rubus fruticosus L. agg.) growing within and in adjacent areas outside the river floodplain. Heavy metal contamination of the Innerste floodplain is a legacy of historical metal ore mining, processing, and smelting in the Harz Mountains. The heavy metal (Cd, Pb, Zn, Cu, Ni, and Cr) contents of previously studied soil samples from eleven floodplain sites along the Innerste River were re-analyzed statistically, and the levels of these metals in blackberry leaves were determined at five sites. Mean concentrations in the floodplain soils were elevated by factors of 4.59 to 28.5 for Cd, 13.03 to 158.21 for Pb, 5.66 to 45.83 for Zn, and 1.1-14.81 for Cu relative to the precautionary limits for soils stipulated by the German Federal Soil Protection and Contaminated Sites Ordinance. Cadmium, Pb, Zn, Cu, and Ni levels in floodplain soils decreased markedly downstream, as did the concentrations of Cd, Zn, and Ni in the leaves of blackberries from within the floodplain. Levels of Cd, Pb, and Zn in leaves of blackberries from within the floodplain significantly exceeded those of specimens from outside the floodplain. The findings of our study highlight the potential of wild blackberry as a biomonitor of soil pollution by Cd, Pb, and Zn and corroborate the massive heavy metal contamination of floodplain soils along the Innerste River observed in previous studies.

Selection and Validation of Candidate Reference Genes for Gene Expression Analysis by RT-qPCR in Rubus

Due to the lack of effective and stable reference genes, studies on functional genes in Rubus, a genus of economically important small berry crops, have been greatly limited. To select the best internal reference genes of different types, we selected four representative cultivars of blackberry and raspberry (red raspberry, yellow raspberry, and black raspberry) as the research material and used RT-qPCR technology combined with three internal stability analysis software programs (geNorm, NormFinder, and BestKeeper) to analyze 12 candidate reference genes for the stability of their expression. The number of most suitable internal reference genes for different cultivars, tissues, and fruit developmental stages of Rubus was calculated by geNorm software to be two. Based on the results obtained with the three software programs, the most stable genes in the different cultivars were RuEEF1A and Ru18S. Finally, to validate the reliability of selected reference genes, the expression pattern of the RuCYP73A gene was analyzed, and the results highlighted the importance of appropriate reference gene selection. RuEEF1A and Ru18S were screened as reference genes for their relatively stable expression, providing a reference for the further study of key functional genes in blackberry and raspberry and an effective tool for the analysis of differential gene expression.