scholarly journals HPLC-Based Chemometric Analysis for Coffee Adulteration

Foods ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 880
Author(s):  
Wai Lok Cheah ◽  
Mingchih Fang

Coffee is one of the top ten most adulterated foods. Coffee adulterations are mainly performed by mixing other low-value materials into coffee beans after roasting and grinding, such as spent coffee grounds, maize, soybeans and other grain products. The detection of adulterated coffee by high performance liquid chromatography (HPLC) is recognized as a targeted analytical method, which carbohydrates and other phenolic compounds are usually used as markers. However, the accurate qualitation and quantitation of HPLC analyses are time consuming. This study developed a chemometric analysis or called non-targeted analysis for coffee adulteration. The HPLC chromatograms were obtained by direct injection of liquid coffee into HPLC without sample preparation and the identification of target analytes. The distinction between coffee and adulterated coffee was achieved by statistical method. The HPLC-based chemometric provided more characteristic information (separated compounds) compared to photospectroscopy chemometric which only provide information of functional groups. In this study, green Arabica coffee beans, soybeans and green mung beans were roasted in industrial coffee bean roaster and then ground. Spent coffee ground was dried. Coffee and adulterants were mixed at different ratio before conducting HPLC analysis. Principal component analysis (PCA) toward HPLC data (retention time and peak intensity) was able to separate coffee from adulterated coffee. The detection limit of this method was 5%. Two models were built based on PCA data as well. The first model was used to differentiate coffee sample from adulterated coffee. The second model was designed to identify the specific adulterants mixed in the adulterated coffee. Various parameters such as sensitivity (SE), specificity (SP), reliability rate (RLR), positive likelihood (+LR) and negative likelihood (−LR) were applied to evaluate the performances of the designed models. The results showed that PCA-based models were able to discriminate pure coffee from adulterated sample (coffee beans adulterated with 5%–60% of soybeans, green mung beans or spent coffee grounds). The SE, SP, RLR, +LR and −LR for the first model were 0.875, 0.938, 0.813, 14.1 and 0.133, respectively. In the second model, it can correctly distinguish the adulterated coffee from the pure coffee. However, it had only about a 30% chance to correctly determine the specific adulterant out of three designed adulterants mixed into coffee. The SE, RLR and −LR were 0.333, 0.333 and 0.667, respectively, for the second model. Therefore, HPLC-based chemometric analysis was able to detect coffee adulteration. It was very reliable on the discrimination of coffee from adulterated coffee. However, it may need more work to tell discern which kind adulterant in the adulterated coffee.

2021 ◽  
Vol 21 (5) ◽  
pp. 1281
Author(s):  
Michael Raharja Gani ◽  
Enade Perdana Istyastono

We developed a method for determining the caffeic acid in spent coffee grounds. The spent coffee ground solution was prepared by blending 3 g spent coffee grounds with 60 mL ethanol/water (40/60 v/v) for 2 h on a hot plate magnetic stirrer (60 °C, 350 rpm). The mixture was filtered and the filtrate was concentrated under vacuum (60 °C) to 5 mL. The method employed a reversed-phase high-performance liquid chromatography with a UV detector. We used a Phenomenex Luna column (250 × 4.6 mm; i.d., 5 µm) under isocratic elution, and the mobile phase was acetonitrile-methanol-aqueous formic acid (10:10:80 v/v), with a flow rate of 0.9 mL/min. Analysis was performed at 324 nm. The column temperature was set at 27 °C temperature. The results showed that this method was selective for quantifying the caffeic acid in spent coffee grounds with good linearity in the range of 1.31–17.07 μg/mL. The detection and quantitation limits were 0.28 and 0.84 μg/mL, respectively. The mean intraday and interday recoveries were 83.80–95.17% and 82.16–97.40%, respectively. Intraday and interday precision expressed as the relative standard deviation (RSD) were below 7.3%. There was 0.17% ± 0.006 w/w caffeic acid in the spent coffee grounds (RSD = 3.63%, n = 3).


Author(s):  
Mayuree Kanlayavattanakul ◽  
Nattaya Lourith ◽  
Puxvadee Chaikul

Abstract Background Coffee beans contain oil with health benefits from fatty acids. The unprocessed and processed coffee beans are mostly identical in coffee oil quality and are substantively supplied for certain industries. However, the cost-effective valorization of specialty ingredients from spent coffee grounds for cosmetics is sparely presented. Linoleic acid-rich spent coffee oil, as a specialty material for skin lightening and antiaging cosmetics, is objectively to be presented. Results Spent coffee oils were prepared by different methods. The most cost-effective material with a high extraction yield, linoleic acid content and unsaturated/saturated fatty acid (UFA/SFA) ratio (13.21  ±  0.25, 32.09% and 0.97) was modified. The modified oil was boosted in linoleic acid (77.20% or 140.57% improvement) and the UFA/SFA ratio (33.12). The physicochemical properties of the oil were applicable for cosmetics as per its safety profiles in B16F10 melanoma and normal human skin fibroblast cells. The oil significantly better inhibited cellular melanogenesis than kojic and linoleic acids (p  <  0.01), with prominent tyrosinase and TRP-2 inhibitions. The cellular antioxidant activity of the oil was comparable to those of ascorbic and linoleic acids. The collagen stimulating efficacy of the oil was significantly better than that of ascorbic but comparable to that of linoleic acid as indicated by the MMP-2 inhibitory activities (p  <  0.01 and p  <  0.001, respectively). Conclusions The oil is a specialty material for skin brightening and skin wrinkle reduction/skin elasticity improvement products. A successive circular bioeconomy of spent coffee ground waste in a more profitable cosmetic industry is indicated. Graphic abstract


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shawn Gouws ◽  
Michael Muller

AbstractThe valorisation of ground coffee beans is discussed in two parts; the first research question relates to the extraction of cold brew from ground coffee beans to provide a healthy cold beverage. Two parameters were investigated: temperature, and the ratio of ground coffee beans to water. This work suggests that cold brew coffee can be extracted between 15 and 20 °C over 2 to 4 h instead of 24 h as outlined in typical cold brew extraction processes. The coffee aroma was the response variable. Part of this investigation was to develop a downstream product from the waste spent grounded coffee bean. This part of the study investigates the production of firelighters from spent ground coffee beans to reduce the impact of dumping significant quantities of spent coffee grounds from coffee houses, restaurants, and baristas on landfill sites, which can lead to environmental problems such as polluting water systems, killing wildlife and disturbing ecosystems. The study used spent ground coffee beans in products such as firelighters to test their efficacy. This application has shown promising results, with the firelighters showing longer burning times for the ignition of log fires while also emitting a gentle, pleasant coffee aroma.


Author(s):  
Firmansyah A. ◽  
Winingsih W. ◽  
Soebara Y S

Analysis of natural product remain challenging issues for analytical chemist, since natural products are complicated system of mixture. The most popular methods of choice used for quality control of raw material and finished product are high performance liquid chromatography (HPLC), gas chromatography (GC) and mass spectrometry (MS). The utilization of FTIR-ATR (Fourier Transform Infrared-Attenuated Total Reflectance) method in natural product analysis is still limited. This study attempts to expand the use of FTIR spectroscopy in authenticating Indonesian coffee powder.The coffee samples studied were taken from nine regions in Indonesia, namely Aceh Gayo, Flores, Kintamani, Mandheling, Papua, Sidikalang, Toraja, Kerinci and Lampung.The samples in the form of coffee bean from various regions were powdered . The next step conducted was to determine the spectrum using the FTIR-ATR (Attenuated Total Reflectance) using ZnSe crystal of 8000 resolution. Spectrum samples, then, were analyzed using chemometrics. The utilized chemometric model was the principal component analysis (PCA) and cluster analysis (CA). Based on the chemometric analysis, there are similarities between Aceh Gayo coffee with Toraja coffee, Mandailing coffee, Kintamani coffee and Flores coffee. Sidikalang coffee has a similarity to Flores coffee; Papua coffee has a similarity to Sidikalang coffee; Lampung coffee has a similarity to Sidikalang coffee, while Kerinci coffee has a similarity to Papua coffee.


2021 ◽  
pp. 002199832110022
Author(s):  
Ahmed Alhelal ◽  
Zaheeruddin Mohammed ◽  
Shaik Jeelani ◽  
Vijaya K Rangari

Semi-crystalline carbon biochar is derived from spent coffee grounds (SCG) by a controlled pyrolysis process at high temperature/pressure conditions. Obtained biochar is characterized using XRD, SEM, and TEM techniques. Biochar particles are in the micrometer range with nanostructured morphologies. The SCG biochar thus produced is used as reinforcement in epoxy resin to 3 D print samples using the direct-write (DW) method with 1 and 3 wt. % loadings. Rheology results show that the addition of biochar makes resin viscous, enabling it to be stable soon after print; however, it could also lead to clogging of resin in printer head. The printed samples are characterized for chemical, thermal and mechanical properties using FTIR, TGA, DMA and flexure tests. Storage modulus improved with 1 wt. % biochar addition up to 27.5% and flexural modulus and strength increased up to 55.55% and 43.30% respectively. However, with higher loading of 3 wt. % both viscoelastic and flexural properties of 3D printed samples drastically reduced thus undermining the feasibility of 3D printing biochar reinforced epoxies at higher loadings.


Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 665 ◽  
Author(s):  
Tizian Klingel ◽  
Jonathan I. Kremer ◽  
Vera Gottstein ◽  
Tabata Rajcic de Rezende ◽  
Steffen Schwarz ◽  
...  

The coffee plant Coffea spp. offers much more than the well-known drink made from the roasted coffee bean. During its cultivation and production, a wide variety of by-products are accrued, most of which are currently unused, thermally recycled, or used as animal feed. The aim of this review is to provide an overview of novel coffee products in the food sector and their current legal classification in the European Union (EU). For this purpose, we have reviewed the literature on the composition and safety of coffee flowers, leaves, pulp, husk, parchment, green coffee, silver skin, and spent coffee grounds. Some of these products have a history of consumption in Europe (green coffee), while others have already been used as traditional food in non-EU-member countries (coffee leaves, notification currently pending), or an application for authorization as novel food has already been submitted (husks, flour from spent coffee grounds). For the other products, toxicity and/or safety data appear to be lacking, necessitating further studies to fulfill the requirements of novel food applications.


Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5592
Author(s):  
Jung-Hoon Kim ◽  
Eui-Jeong Doh ◽  
Guemsan Lee

It is thought that the therapeutic efficacy of Morus alba L. is determined by its biological compounds. We investigated the chemical differences in the medicinal parts of M. alba by analyzing a total of 57 samples (15 root barks, 11 twigs, 12 fruits, and 19 leaves). Twelve marker compounds, including seven flavonoids, two stilbenoids, two phenolic acids, and a coumarin, were quantitatively analyzed using a high-performance liquid chromatography-diode array detector and chemometric analyses (principal component and heatmap analysis). The results demonstrated that the levels and compositions of the marker compounds varied in each medicinal part. The leaves contained higher levels of six compounds, the root barks contained higher levels of four compounds, and the twigs contained higher levels of two compounds. The results of chemometric analysis showed clustering of the samples according to the medicinal part, with the marker compounds strongly associated with each part: mulberroside A, taxifolin, kuwanon G, and morusin for the root barks; 4-hydroxycinnamic acid and oxyresveratrol for the twigs and skimmin; chlorogenic acid, rutin, isoquercitrin, astragalin, and quercitrin for the leaves. Our approach plays a fundamental role in the quality evaluation and further understanding of biological actions of herbal medicines derived from various medicinal plant parts.


2021 ◽  
Vol 947 (1) ◽  
pp. 012044
Author(s):  
Trấn Thi Thu Trà ◽  
Lê Nguyên Phúc ◽  
Võ Thi Ngoc Yến ◽  
Lê Thánh Sang ◽  
Nguyễn Thi Anh Thu ◽  
...  

Abstract Spent coffee ground (SCG) is the main by-product of the instant coffee industry. In this study, wheat flour and dried SCG powder were used in the production of cookies with high fiber and antioxidant content. The objective of the study was to evaluate the effects of SCG ratio in the cookie formulation on nutritional quality, physical properties and sensory overall acceptability of the product. SCG is a rich source of dietary fiber. In 100 g dry weight of SCG, the total fiber and phenolic contents were 76.6 ± 0.58% and 3828±12 mg GAE/100g dry basis, respectively. When the SCG ratio increased from 0 to 0.25 of the composite flour weight, the dough had increased hardness and reduced adhesiveness, cohesiveness and springiness. An increase in the SCG ratio in the cookie formulation also decreased the diameter and thickness of the product but enhanced its hardness. Cookie samples supplemented with SCG had higher dietary fiber and phenolic content as well as a higher antioxidant activity than the control sample. Cookie samples were considered as high fiber food when the SCG ratio was 0.1 or higher. The use of SCG reduced the overall acceptability of cookies. When the ratio of SGC powder varied from 0.1 to 0.2, a sensory score of the obtained cookies was acceptable.


Author(s):  
Raluca Maria Pop ◽  
Florina Csernatoni ◽  
Floricuta Ranga ◽  
Florinela Fetea ◽  
Carmen Socaciu

. High performance liquid chromatography (HPLC) with UV detection is nowadays the reference method to identify and quantify the biomarkers of quality and authenticity of plants and food supplements. Seven medicinal plants were collected from wild flora: Taraxacum officinalis (1), Cynara scolimus (2), Silybum marianum (3), Hypericum perforatum (4),  Chelidonium majus (5), Lycopodium clavatum (6) and  Hippophae rhamnoides (7)  leaves and fruits.  Two products (A and B) were obtained by mixing individual plant powders. Therefore product A was obtained by mixing dandelion, artichoke and milk thistle, 1:1:1 while product B by mixing St John’s wort, Celandine and Wolf’s claw, 1:1:1. The methanolic extracts of individual plants as well as three different extracts of products A and B (using acidulated water, neutral water and acidulated methanol) were analyzed using HPLC-UV for their phenolics’ fingerprint and composition. The qualitative (untargeted analysis) and quantitative (targeted analysis) results were further compared using Principal Component Analysis (PCA) in order to identify their specific biomarkers. Thus, quantitative evaluation of individual phenolics in case of individual plants and products A and B extracts, showed specific and significant differences of composition. Both products A and B contained elagic acid as major compound. For product A, good biomarkers were trans-cinnamic, chlorogenic, caffeic and p-coumaric acids, as well silymarin and silibine originating from milk thistle. For product B, good biomarkers were quercetin and kaempherol, gallic and protocatecuic acids, this product being rich in flavonoids. In conclusion, HPLC-UV coupled with PCA analysis proved to be a rapid and useful way to identify the main biomarkers of plants’ authentication, as well of final products’ quality and safety.


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