Acorn-based Coffee Boosts Antioxidants With Minimal Health Risk

Researchers uncover really oak acorns turned into coffee-like drinks, battalion potent antioxidants while staying safely beneath toxin limits, making them a astonishing caller superfood for health-conscious java drinkers.

Study: Oak Acorns arsenic Functional Foods: Antioxidant Potential and Safety Assessment. Image credit: New Africa/Shutterstock.com

Thermally processed oak acorns (Quercus robur) in their autochthonal flour shape are rich successful antioxidants and are safe for consumption. A caller study successful Foods investigated whether different processing methods effect bioactive compounds successful acorn-based products.

Why are oak acorns a rich | root of nutrient and beverage?

Acorns are nan nuts of nan oak character (Quercus spp.), which person been traditionally utilized successful galore cultures for centuries. The oak character belongs to nan Fagaceae family and is wide distributed crossed Asia, Europe, and North America. Numerous studies person demonstrated that Quercus type are rich | successful bioactive compounds, including phenolic acids, flavonoids, and tannins, which person antioxidant, anticancer, and antimicrobial properties.

Over nan years, nan depletion of oak acorns has declined owed to their precocious tannin content, which makes them bitter and impairs nutrient absorption by binding to proteins and minerals. However, a caller surge successful acorn depletion has been noted owed to its sustainability and health-promoting properties. For example, acorn flour has been utilized arsenic a gluten-free and fiber-rich replacement to wheat flour, enhancing nan nutritional and sensory properties of galore baked products, specified arsenic bread, cakes, and cookies.

Recently, galore health-conscious individuals pinch dietary restrictions person substituted accepted java pinch alternatives specified arsenic chicory, barley, spelt, dandelion, and acorns. These alternatives are mostly rich | successful vitamins, fiber, minerals, and phenolic acids (e.g., gallic, caffeic, and chlorogenic acid). Phytochemical study has revealed that acorns incorporate a precocious attraction of carbohydrates, lipids, dietary fiber, proteins, and unsaturated fatty acids.

There is simply a deficiency of investigation regarding nan antioxidant activity of Q. robur fruits, peculiarly successful coffee-like beverages made from roasted acorns. Acorn roasting is simply a modular pre-treatment process performed to heighten flavor, which alters nan chemic floor plan of nan seeds. A erstwhile study has indicated that erstwhile mixed pinch ginseng, acorn-based beverages person a superior antioxidant imaginable compared to commercialized java alternatives.

Thermal processing astatine precocious temperature, typically supra 200°C, leads to nan statement of polycyclic aromatic hydrocarbons (PAHs) that person imaginable mutagenic and carcinogenic properties. Although java and java substitutes are exempt from European Union PAH limits, immoderate studies person identified these harmful chemicals, peculiarly benzo[a]anthracene and anthracene. Therefore, analyzing nan benefit-to-risk floor plan of roasted acorns utilized arsenic java substitutes is important. However, nan study confirmed that benzo[a]pyrene, nan astir concerning PAH carcinogen, was not detected successful immoderate acorn product, further supporting their safety

About nan study

The existent study investigated nan PAH contented and nan antioxidant imaginable of coffee-like beverages prepared from roasted Q. robur acorns. Oak acorns were processed utilizing different methods, and each sample was individually assessed.

Oak acorns were collected from nan Kosmaj mountain, air-dried astatine room temperature, and powdered to nutrient “acorn flour”. In addition, 100 grams of barren acorns were roasted astatine 200°C for 30 minutes, and were powdered arsenic “coffee”. For different sample type, 100 grams of dry-shelled acorns were coarsely chopped and soaked successful h2o (60 to 70 °C) for 30 minutes. After repeating this soaking process a mates of times, nan oak acorns were dried astatine 40°C for astir 3 hours. Subsequently, these acorns were roasted astatine 200 °C for 30 minutes and powdered to make “super coffee”. Methanol, acetone, and hexane extracts of acorn java and flour were prepared.

Study findings

Highly polar solvents, specified arsenic methanol and aqueous acetone, readily extracted phenols and flavonoids from Quercus robur acorns. Total phenol contented (TPC) successful methanol extracts was estimated to beryllium 66.53 mg gallic acerb balanced (GAE) per gram barren weight (dw), while acetone extracts yielded 24.21 mg GAE/g dw. This quality successful phenolic contented is because acetone is little polar than methanol.

Both thermally processed java and ace java indicated a 15% and 9% summation successful TPC successful methanol and acetone extracts, respectively, comparative to earthy flour. This summation successful phenolic attraction could beryllium attributed to nan statement of low-molecular-weight phenolics during roasting.

Similarly, nan highest full flavonoid contented (TFC) was recovered successful nan methanolic extracts of nan acorn flour sample, followed by “coffee” and “super coffee”. Flavonoid levels declined from astir 181.5 mg RE/g dw successful flour to 161.7 mg RE/g dw successful “coffee” and 150.7 mg RE/g dw successful “super coffee”, confirming thermal degradation of these compounds. Regardless of solvent polarity, nan autochthonal acorn flour consistently exhibited nan highest flavonoid levels compared to its roasted counterparts. The alteration successful TFC post-roasting confirms nan susceptibility of flavonoids to thermal degradation.

The antioxidant activity of acorn extracts was evaluated utilizing ABTS, DPPH, CUPRAC extremist scavenging assays, and FRAP and TRP particle transportation assays, which indicated precocious antioxidant properties. Compared to nan hexane extract, methanol extracts of each samples exhibited nan highest antioxidant activity, reflecting nan minimal extraction of hydrophilic phenolics, arsenic indicated by trolox equivalents (TE)/g dw estimates. However, acetone extracts exhibited a marginally higher DPPH scavenging activity, implying that definite mid-polarity antioxidants are amended extracted by acetone.

Methanol CUPRAC values reached up to 584 mg TE/g dw, ABTS values were astir 127 mg TE/g dw, and FRAP values approached 200 mg Fe/g dw, each of which comparison favorably to emblematic roasted java beans.

The FRAP assay revealed that thermal processing accrued antioxidant powerfulness successful nonpolar extracts. FRAP values roseate dramatically post-roasting, by astir 100% successful methanol, 124% successful acetone, and 375% successful hexane extracts. This highlights really Maillard guidance products formed during roasting importantly heighten antioxidant capacity, peculiarly successful lipophilic fractions.

The bioactive estimates of “super coffee” decreased pinch expanding lipophilicity of nan solvent. The sums of TPC for acorn flour, “coffee”, and “super coffee” were 89.2, 92.9, and 87 mg GAE/g dw, respectively, while nan sums of full simplification imaginable (TRP) were 6.86, 7.0, and 6.99 mg AAE/g dw, respectively. The studied samples' antioxidant activity was associated pinch nan full contented of phenols and flavonoids.

In nan existent study, “coffee” and “super coffee” samples contained PAHs that were 2 to 3 times higher than those successful autochthonal acorn flour. “Super coffee” was recovered to incorporate some low-molecular-weight (LMW) and high-molecular-weight (HMW) PAHs. Since nary of nan PAHs were coming successful autochthonal acorn flour (aside from indeno[1,2,3-cd] pyrene astatine ~8.8 ng/g dw, apt from biology contamination), it indicates that roasting was nan source. The researchers statement that only astir 30% of PAHs transportation into brewed acorn infusions, reducing existent dietary exposure.

The full PAH level reached 222 ng/g dw successful “coffee” and 290 ng/g dw successful “super coffee”, comparable to nan ranges reported for different java substitutes. The superior PAH4 marker was benzo[a]anthracene (34 – 39.8 ng/g) while chrysene, benzo[b]fluoranthene, and benzo[a]pyrene were not detected.

Conclusions

The existent study demonstrated that autochthonal and heat-treated acorns incorporate a precocious magnitude of phenol and flavonoid compounds. Methanol extracts exhibited nan highest antioxidant activity. The absence of carcinogenic PAH4 marker successful nan autochthonal flour indicated that unprocessed acorn powder is safe for dietary use. 

Despite measurable PAHs successful roasted samples, each levels remained good beneath EU regulatory limits for cocoa-based products, suggesting minimal wellness consequence erstwhile consumed arsenic java substitutes.

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