光谱分析法应用于咖啡成分的测定和咖啡种类的鉴别

应用光谱分析法测定现磨咖啡、速溶咖啡和菊苣咖啡的成分。通过电感耦合等离子体发射光谱(ICP-ES)测定咖啡样品的矿物质元素。分别采用紫外(UV)和傅里叶红外(FTIR)光谱法测定咖啡因和有机物的含量,草酸的测定需要采用氧化还原滴定法来完成。基于咖啡因、草酸和矿物质的测定,分析现磨咖啡、速溶咖啡和菊苣咖啡的差异。实验表明,咖啡因在速溶咖啡中的含量比现磨咖啡的要高出2～3倍;草酸在速溶咖啡中的含量明显高于现磨咖啡;矿物质元素Mg,P,Zn在现磨咖啡中的含量比速溶咖啡的要低,而Cu的含量则比速溶咖啡高出好几倍;菊苣咖啡中的矿物质含量总体上比速溶咖啡的要低。此外,我们在不同种类的咖啡中测定Ti的含量,在菊苣咖啡中检测到Cu,Ti,Zn元素。作为一种快速检测技术,FTIR光谱可以用于鉴别现磨、速溶和菊苣咖啡,并能够检验咖啡因和草酸的存在。     

高效液相色谱-串联质谱法同时测定烟草中5种Amadori化合物

建立了高效液相色谱-三重四极杆质谱（HPLC-QqQ MS）联用定量分析烟草中5种Amadori前香物质的方法。样品经含5%（v/v）甲醇的水提取后,采用Waters XBridge^TM Amide色谱柱（250 mm×4.6 mm,3.5 μm）、以甲醇-水为流动相进行分离,采用多反应监测（MRM）模式测定烟草样品中5种Amadori化合物的含量。结果表明,5种Amadori化合物的峰面积与质量浓度的线性关系良好,相关系数r为0.9895~0.9989;定量限（S/N=10）在10.18~44.58 μg/L,检出限（S/N=3）在3.51~14.86 μg/L;平均加标回收率为92.6%~123.6%,相对标准偏差（RSD）小于9.4%。本方法操作简便、灵敏度高、分析速度快,可以用于烟叶及卷烟中5种主要Amadori类物质的含量测定。     

Ultrasound-Assisted Hydrodistillation of Essential Oil from Celery Seeds (Apium graveolens L.) and Its Biological and Aroma Profiles

The aim of the research was to increase the efficiency of the hydrodistillation process and determine the volatile composition, biological activity, and aroma profile of essential oil from celery seeds (Apium graveolens L.). The essential oil was extracted from the plant material by ultrasonic hydrodistillation with higher efficiency when compared with classical hydrodistillation. The antimicrobial activity was evaluated using the impedimetric method for the bacteria Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and yeast Candida vini as well as moulds Aspergillus niger and Penicillium expansum with minimal inhibitory concentration (MIC) (μL/mL) values: 30, 10, 20, 3, 30, 40, and 40, respectively. The oil possessed very weak 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant activity with the half maximal inhibitory concentration (IC₅₀) value of 81.6 g/L. Initial studies of the aroma profile indicated that the perception of the fragrance of the oil could be related to the sex of the panellists. According to women, the fragrance of celery seeds oil was intense herb-like. From the men’s point of view, it had a fresh, mossy, and mushroom scent.     

Selectivity in separation using π electron-rich stationary phases for the comprehensive two-dimensional analysis of café espresso

The multidimensional high-performance liquid chromatography separations of the complex sample matrix found in café espresso coffee were completed on the propyl phenyl and butyl phenyl columns that contain 3 and 4 carbon atoms in the spacer chain, respectively. Phenyl type stationary phases are able to undergo unique π-π interactions with aromatic compounds. Previous works have found that there are differences in retention characteristics between these chain lengths and this was explored further here. It was found that when analysing the separations by quadrants, using a geometric approach to factor analysis and by measuring the normalised mean radius, subtle differences in the separations were observed and the butyl phenyl phase was more selective for the high to medium polarity species. However, there was very little difference in separation behaviour for the hydrophobic components within the coffee sample. Overall, the analysis of the entire separation showed very little difference.     

Efficient Synthesis of β‐Primeverosides as Aroma Precursors by Transglycosylation of β‐Diglycosidase from Penicillium multicolor

The enzyme activity transferring a β‐primeverosyl unit was found from culture filtrates of Penicillium multicolor IAM7153 and was useful for synthesizing a series of β‐primeverosides via a β‐primeverosyl transfer reaction in an aqueous‐organic biphasic system. With the acceptors benzyl alcohol, 2‐phenylethanol, and (Z)‐3‐hexenol, the enzyme induced the transfer products benzyl, 2‐phenylethyl, and (Z)‐3‐hexyl β‐primeverosides in high yields of 51% to 70% based on the donor added. When geraniol and eugenol were used as acceptors, the corresponding geranyl and eugenyl β‐primeverosides were obtained in lower yields of 8% to 12%. The enzyme was an excellent tool for producing naturally occurring β‐primeverosides on a mmol scale.     

A new approach based on off‐line coupling of high‐performance liquid chromatography with gas chromatography‐mass spectrometry to determine acrylamide in coffee brew

A new method based on off‐line coupling of LC with GC in replacement of conventional sample preparation techniques is proposed to analyze acrylamide in coffee brews. The method involves the preseparation of the sample by LC, the collection of the selected fraction, its concentration under nitrogen, and subsequent analysis by GC coupled with MS. The composition of the LC mobile phase and the flow rate were studied to select those conditions that allowed separation of acrylamide without coeluting compounds. Under the conditions selected recoveries close to 100% were achieved while LODs and LOQs equal to 5 and 10 μg/L for acrylamide in brewed coffee were obtained. The method developed enabled the reliable detection of acrylamide in spiked coffee beverage samples without further clean‐up steps or sample manipulation.     

Effects of Methyl Jasmonate and Nano-Methyl Jasmonate Treatments on Monastrell Wine Volatile Composition

The application of methyl jasmonate (MeJ) as an elicitor to enhance secondary metabolites in grapes and wines has been studied, but there is little information about its use in conjunction with nanotechnology and no information about its effects on wine volatile compounds. This led us to study the impact of nanoparticles doped with MeJ (Nano-MeJ, 1mM MeJ) on the volatile composition of Monastrell wines over three seasons, compared with the application of MeJ in a conventional way (10 mM MeJ). The results showed how both treatments enhanced fruity esters in wines regardless of the vintage year, although the increase was more evident when grapes were less ripe. These treatments also achieved these results in 2019 in the cases of 1-propanol, ß-phenyl-ethanol, and methionol, in 2020 in the cases of hexanol and methionol, and in 2021, but only in the case of hexanol. On the other hand, MeJ treatment also increased the terpene fraction, whereas Nano-MeJ, at the applied concentration, did not increase it in any of the seasons. In summary, although not all families of volatile compounds were increased by Nano-MeJ, the Nano-MeJ treatment generally increased the volatile composition to an extent similar to that obtained with MeJ used in a conventional way, but at a 10 times lower dose. Therefore, the use of nanotechnology could be a good option for improving the quality of wines from an aromatic point of view, while reducing the necessary dosage of agrochemicals, in line with more sustainable agricultural practices.