Volatile Components and Preliminary Antibacterial Activity of Tamarillo (Solanum betaceum Cav.)

Chemical constituents and antimicrobial activity of the aerial part of Solanum betaceum Cav. (Solanaceae)

A new saponin namely diosgeninoside (25 R-spirost-5-en-3-O-[β-D-glucopyranosyl (1→2) - β-D-glucuronic acid]) and a new fatty acid betacic acid: (Z)-8(S*),9(S*),10(R*)-trihydroxy-11-octadecenoic acid together with six known compounds: N-trans-coumaroyl tyramine, ergosta-7,22-dien-3β,5α,6β-triol, β-sitosterol, and β-sitosterol-3-O-β-D-glucopyranoside, L-threitol and soya-cerebroside I were isolated from the methanolic extract of Solanum betaceum. The structures were elucidated by interpretation of their 1D and 2D NMR spectra and spectrometric data. The methanolic extract, the EtOAc and n-BuOH fractions, and several isolated compounds were tested for antibacterial activity against four bacteria (Staphylococcus aureus; Staphylococcus epidermidis; Escherichia coli; and Pseudomonas aeruginosa). The methanolic extract and the EtOAc fraction showed moderate activity against Staphylococcus aureus and Pseudomonas aeruginosa with MIC value of 128 µg/mL. Compound 1 showed moderate activity against Staphylococcus aureus with MIC value of 64 µg/mL.

Tamarillo (Solanum betaceum Cav.) wastes and by-products: Bioactive composition and health benefits

Introduction

During processing, a large amount of by-products is produced from tamarillo fruits in the form of stalks, outer skins, and pomace (residual seeds and inner skins). This material is a renewable source of bioactive compounds with high economic value and positive effects on human health. Previous reviews have focused on the ethnobotanical, traditional uses, and phytochemistry of the tamarillo fruit. This report aims to compile production and cultivation data, as well as the valorization of this agro-industrial residue, green extraction methods used for extracting the bioactive compounds, and their biological activity.

Method

In this study, a literature search was conducted in five scientific databases: Web of Science, ScienceDirect, Scopus, PubMed, and Google Scholar to retrieve research published in English, Spanish, or Portuguese between 2009 and 2024, which mentions the composition and extraction methods of bioactive compounds from tamarillo wastes and by-products and the health benefits associated with these compounds. The data extracted was compiled and shown in this scoping review.

Results

Tamarillo wastes and by products have a rich nutritional and bioactive composition, including high protein, vitamins A and C, minerals, dietary fiber, sugars, terpenes, flavonoids, carotenoids, anthocyanins, and other phytochemicals. Green methods have been effective, yielding high amounts of these compounds while preserving their integrity. Natural polyphenols have shown antioxidant, anticholinesterase, anti-inflammatory, antimicrobial, anti-diabetic, and anti-obesity properties. The antioxidant fibers, mucilage, and pectin of the pomace contribute to improved intestinal health.

Conclusion

Therefore, these wastes and by-products have potential uses as natural colorant, antioxidants, supplements, functional foods, active biobased films, and in pharmaceutical and cosmeceutical sectors due to their effective bioactive molecules. Future research should focus on the use of tamarillo by-products as a source of functional ingredients in several other formulations that are still little explored, as well as their use as a natural colorant and antioxidant. More studies are necessary on the composition-activity relationship, physiological mechanisms, and clinical response.

Chemical composition and antimicrobial activity of essential oils and various extracts of endemic Onosma malatyana (Boraginaceae) from Anatolia

The chemical contents of the endemic Onosma malatyana roots collected from Malatya/Türkiye were determined using the hydrodistillation and the soxhlet methods and antimicrobial activity analysis of the extracts was also performed. The hydrodistillation method applied to the roots of O.malatyana resulted in identifying 31 compounds according to their retention times in GC-MS analysis. Additionally, crude ethyl acetate and crude oil etheric extracts of O.malatyana roots contained 14 compounds each. This research identified that the main component of the essential oil obtained by the hydrodistillation method was palmitic acid comprising 56.48% of the total composition. Additionally, in the crude petroleum etheric extract, oleic acid methyl ester (31.22%); and palmitic acid (24.69%) were identified as the main components in the crude ethyl acetate extract. The results of the antimicrobial activities indicated that O.malatyana root extracts were particularly effective against Gram-positive bacteria, specifically S. aureus and B. subtilis.

Quality criteria, chemical composition and antimicrobial activity of the essential oil of Mentha suaveolens Ehrh

The aim of the present study is the valorization of the essential oil of Mentha suaveolens Ehrh. The research plan and methods included 3-axis: the first axis consists of studying the organoleptic and physicochemical characterization of the essential oil, the second is the chemical analysis carried out by Gas Chromatography/Mass Spectrometry (GC/MS) and the third consists of evaluating its antimicrobial activity against selected microorganisms. The results obtained for the organoleptic and physicochemical properties are as follows: appearance: Liquid, mobile and clear, odor: Strong odor characteristic of Mentha suaveolens Ehrh, color: Pale yellow; relative density (0.92), miscibility with ethanol (1V/2V), freezing point (Tfreezing < -10 °C), refractive index (1.5256), rotating power (+0.825), acid index (1.68), ester index (68.44), saponification index (70.13) and iodine index (12.05).Chemical analysis identified 69 compounds which are mostly oxygenated monoterpenes such as piperitenone oxide (32.55%), pulegone (10.14%), piperitone oxide (8.34%), etc. The microbiological tests were carried out by an agar diffusion test using the essential oil of Mentha suaveolens Ehrh. The microbiological tests were carried out by a diffusion test on agar, these tests are carried out on six microbial strains (five bacteria and one yeast).The inhibitory effect of our oil is well marked against bacteria: Proteus mirabilis (17.50 ± 0.70 mm at 50 μL/mL), Enterococcus faecalis (17.00 ± 1.00 mm at 50 μL/mL) and Staphylococcus coagulase negative (16.33 ± 0.57 mm at 50 μL/mL) while it was moderate against Escherichia coli (14.33 ± 1.15 mm at 50 μL/mL) and Streptococcus spp (13.00 ± 0.00 mm at 50 μL/mL) as well as against yeast, Candida albicans (15.33 ± 1.52 mm at 50 μL/mL). It appears from these results that our oil is of high quality and can be used in several areas. The results obtained are therefore promising and thus open the way for manufacturers to use this essential oil of Mentha suaveolens Ehrh in the pharmaceutical, cosmetic, agricultural and food industries.

Identifying sensory attributes of Korean rice wine (makgeolli) using sensory evaluation and chemical analysis

Makgeolli is a traditional alcoholic beverage in Korea; however, research on makgeolli is limited in foreign markets such as New Zealand. This study seeks to identify sensory descriptors that best describe makgeolli among New Zealand consumers. Four methods of making makgeolli have been identified based on different processing times and the number of fermentation stages. Chemical analysis and sensory evaluation were carried out to establish the different sensory and flavor properties of the four different makgeolli samples. Chemical analysis using SPME-GC-MS was employed to understand the volatile compounds present in the four makgeolli samples, while two sensory tests were carried out simultaneously using Check-All-That-Apply (CATA) and Just-About-Right (JAR). A total of 45 volatile compounds were identified using SPME-GC-MS, and examples of major volatiles include 2-methyl-1-propanol (alcoholic flavor), limonene (citrus-like flavor), and hexanal (green/grass-like flavor). One hundred and twenty-nine subjects (n = 68 females) completed the sensory evaluation and were analyzed for this study. Female subjects tend to rate overall acceptance of makgeolli higher than male subjects; both subjects preferred 1SF-YN with the highest mean hedonic score, and the least preferred makgeolli was 1SF-N. From CATA, attributes such as apple, apricot, peach, sweet taste, and bubbly texture were statistically significant when describing makgeolli. For JAR, a high proportion of subjects indicated that sourness was too much in three of the four makgeolli samples. PRACTICAL APPLICATION: Research on rice wine in Western markets such as New Zealand is limited, and this study gives insight into how New Zealand consumers perceive Korean rice wine (makgeolli). Sensory participants in this study indicated that makgeolli is too sour and lacks sufficient sweetness in the majority of the samples examined. When launching makgeolli to the New Zealand market, practitioners need to optimize sweetness and reduce sourness to increase overall liking. Sensory terms used by subjects describing makgeolli include cider, apple, and sour.

Minimal Inhibitory Concentrations of Thymol and Carvacrol: Toward a Unified Statistical Approach to Find Common Trends

Thymol and carvacrol are some of the most important and used components of Essential oils (EOs); they are widely studied, and there are much data available in the literature. Their Minimal Inhibitory Concentration (MIC) values found in the literature from 2005 to present were used to assess the bioactivity toward yeasts, molds, Gram-positive bacteria, and Gram-negative bacteria, as well as on some bacterial species/serotypes (Salmonella sp., Escherichia coli, E. coli O157:H7, lactic acid bacteria, Listeria monocytogenes, Staphylococcus aureus, S. epidermidis, etc.) to find possible common trends or differences between the two compounds and among the tested species. The results were quite interesting and pointed out that there is a common range for the MIC of thymol and carvacrol for some bacterial species (150-400 mg/L), with some exceptions to this generalized statement. In addition, the statistics pointed out that bacteria could experience homogeneous (S. epidermidis, E. coli O157:H7) or heterogeneous trends (for example, Salmonella sp.) depending on the existence of possible sub-species or different experimental set-ups. Moreover, this paper suggests that there are some drawbacks and issues that should be solved for the effective use of EOs, which are the strong variability among the microorganisms and the lack of standard protocols and reference strains.

Powdered Beverage from Native Plants from Argentina (Zuccagnia punctata and Solanum betaceum) Obtained by Spray-Drying: A Promising Source of Antioxidant Compounds

In previous studies, the Argentinean native plants called Zuccagnia punctata (jarilla, pus pus, lata) and Solanum betaceum (chilto, tree tomato) were reported as new natural sources of antioxidant compounds, mainly chalcones, anthocyanins and rosmarinic acid derivates. The present study deals with the production of antioxidant beverages of Z. punctata (Zp) extract and chilto juice with honey as sweetener. A Zp extract and red chilto juice were obtained according to Food Code and characterized. The beverages were formulated by using maltodextrin (MD) with two dextrose equivalents (DE), 10 and 15, and then spray-dried at an inlet air temperature of 130 °C. The physicochemical, microscopical, phytochemical and functional characteristics of the powders were surveyed. The experiments carried out showed good physical properties for both formulations showing high water solubility with adequate features for handling, transport and storage. The chromatic parameters of both powdered beverages indicate orange-pink tones regardless of the wall material used. The total polyphenol and flavonoid content in the beverages were kept after spray-drying (92 and 100%, respectively). The anthocyanins were less stable under drying conditions (yield 58%). Both powdered beverages showed high scavenger capacity on ABTS^•+, HO^• and H₂O₂ (SC₅₀ between 3.29 to 41.05 µg GAE/mL) and were able to inhibit xanthine oxidase (XOD) activity (CI₅₀ between 91.35 and 114.43 µg GAE/mL). The beverages were neither toxic nor mutagenic in the concentration range with biological activity. The results obtained in the present work scientifically support the use of the powdered beverages of Argentinean native plants as antioxidant.

Solanum betaceum Fruits Waste: A Valuable Source of Bioactive Compounds to Be Used in Foods and Non-Foods Applications

The fruit supply chain generates large amounts of waste that are often used as animal feed and in the production of both composts and fertilizers and biogas (anaerobic digestion). Since these types of procedures imply high economic costs related to drying, storage, and transport processes, more efficient and environmentally friendly utilization and recycling of this kind of waste are becoming significant for governments and industries. However, improper waste disposal increases the burden on the environment. Many of these fruit wastes, such as Solanum betaceum fruit waste, viz., peels, seeds, and pomace, could be considered potent bio-resource materials for several applications in the food and non-food industries due to their richness in valuable compounds. The basic composition of Solanum betaceum fruits seed has a high content of protein (20%), fiber (around 25%), sugar (11-20%) and low lipid content (0.4%), while S. betaceum peel has a low content of sugar (2-9%), protein (8-10%) and lipid (0.2-0.8%) and high fiber content (23%). Regarding the phytochemicals, the wastes have a high level of phenolics (0.2-0.6%) and pigments such as anthocyanins (0.06%). The inherent bioactive compounds of waste can be used as natural ingredients for foods, cosmetics, medicines, and the production of packaging materials production. Along this line, the present review covers all possible approaches for the valorization of S.betaceum waste in the food and non-food sectors.

Simultaneous Quantification of Organic Acids in Tamarillo (Solanum betaceum) and Untargeted Chemotyping Using Methyl Chloroformate Derivatisation and GC-MS

Sixteen organic acids were quantified in peel and pulp of Amber, Laird’s Large and Mulligan cultivars of tamarillo using GC-MS. Fourteen of these compounds had not previously been quantified in tamarillo. An untargeted metabolomics approach was used in parallel to identify and quantify 64 more metabolites relative to the internal standard, indicating abundances of glutamic acid, pro-line, aspartic acid and γ-aminobutyric acid as well as lower concentrations of several other essential fatty acids and amino acids. The main findings were that total organic acid concentration was significantly higher (p < 0.05) in pulp than in peel, with the highest concentration seen in Mulligan pulp (219.7 mg/g DW). Remarkably, after citric acid, the potent bactericide itaconic acid was the second most abundant organic acid. At least 95% of organic acids in tamarillo were one of these two acids, as well as cis-aconitic, malic and 4-toluic acids. Differences between cultivar chemotypes were as substantial as differences between tissues. These results suggest that the bitter flavour of the peel does not result from organic acids. The combination of targeted and untargeted metabolomics techniques for simultaneous qualitative and quantitative investigation of nutrients and flavours is efficient and informative.

Effect of Tamarillo Fortification and Fermentation Process on Physicochemical Properties and Nutrient and Volatiles Content of Yoghurt

Bright-red Laird’s Large tamarillo is a unique and under-utilised fruit that is a dietary source of carotenoids, vitamins C and E, and dietary fibre. The effects of the addition of freeze-dried tamarillo powder (5–15%) to milk and yoghurt starter either before (PRE) or after (POS) fermentation on physicochemical properties were examined. Using LC-MS and GG-MS, nutrient and volatile contents of tamarillo yoghurt were also examined. The addition of tamarillo prior to fermentation was associated with a more yellow colour and higher concentrations of tocopherol compared to when tamarillo was added after fermentation. Higher elastic modulus, PUFAs, pro-vitamin A content, and vitamin C retention were observed for POS than PRE. All tamarillo yoghurts showed improvement in syneresis, lower lactose content, and higher concentrations of antioxidant vitamins than the commercial premium-assorted fruits yoghurt from New Zealand Food Composition Data. Yoghurt fortified with tamarillo powder offers the potential for the development of a high-value nutritional product that could be a good source of vitamin C and a source of vitamin E and β-carotene, and maintain the volatiles that give tamarillo its distinctive flavour.

Nutritional and Volatile Characterisation of Milk Inoculated with Thermo-Tolerant Lactobacillus bulgaricus through Adaptive Laboratory Evolution

In this study, thermo-tolerant strain of Lactobacillus bulgaricus (L. bulgaricus) was developed using gradual increase in temperature to induce Adaptive Laboratory Evolution (ALE). Viable colony count of 1.87 ± 0.98 log cfu/mL was achieved at 52 °C, using MRS agar supplemented with 2% lactose. Changes in bacteria morphology were discovered, from rod (control) to filament (52 °C) to cocci after frozen storage (−80 °C). When milk was inoculated with thermo-tolerant L. bulgaricus, lactic acid production was absent, leaving pH at 6.84 ± 0.13. This has caused weakening of the protein network, resulting in high whey separation and lower water-holding capacity (37.1 ± 0.35%) compared to the control (98.10 ± 0.60%). Significantly higher proteolytic activity was observed through free amino acids analysis by LC-MS. Arginine and methionine (237.24 ± 5.94 and 98.83 ± 1.78 µg/100 g, respectively) were found to be 115- and 275-fold higher than the control, contributing to changing the aroma similar to cheese. Further volatile analysis through SPME-GC-MS has confirmed significant increase in cheese-aroma volatiles compared to the control, with increase in diacetyl formation. Further work on DNA profiling, metabolomics and peptidomics will help to answer mechanisms behind the observed changes made in the study.