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Potato taste defect (PTD) is a flavor defect in East African coffee associated with Antestiopsis orbitalis feeding and 3-isopropyl-2-methoxypyrazine (IPMP) in the coffee. To elucidate the manifestation of PTD, surface and interior volatile compounds of PTD and non-PTD green coffees were sampled by headspace solid phase microextraction and analyzed by gas chromatography mass spectrometry. Principal component analysis of the chromatographic data revealed a profile of surface volatiles distinguishing PTD from non-PTD coffees dominated by tridecane, dodecane, and tetradecane. While not detected in surface volatiles, IPMP was found in interior volatiles of PTD coffee. Desiccated antestia bugs were analyzed by GCMS, revealing that the three most prevalent volatiles were tridecane, dodecane, and tetradecane, as was found in the surface profile PTD coffee. Coffee having visible insect damage exhibited both a PTD surface volatile profile and IPMP in interior volatiles, supporting the hypothesis linking antestia bug feeding activity with PTD profile compounds on the surface and IPMP in the interior of the beans.

The synthesis of 18-membered macrocyclic ligands containing saturated amine and either pyridine or furan heterocyclic units is described. The protonation equilibria were studied by potentiometric titrations in which four protonation steps were observed for each ligand in the pH ranges 3-12. The protonation mechanism of these macrocyclic ligands was determined from potentiometric titrations followed by NMR and is consistent with protonation of only the saturated amine groups in the pH range studied. The formation constants for complexes of pyo2[18]dieneN6 with Ca(II), Mg(II), Mn(II), Cu(II), Zn(II), Cd(II), La(III), and Gd(III), determined potentiometrically, follow the order of the Irving-Williams series and are consistent with 1:1 metal ion binding. Furthermore, py02[18]dieneN6 binds as well or better than its saturated homolog, [ 18]aneN6. In contrast, furo2[l 8]aneN402 doesnot bind effectively in comparison to the saturated homolog, trans-[ 18]aneN402. The difference in binding may be due to a combination of enthalpic (polarity of ligating groups and steric strain of the ligand) and entropic (rigidity of the ligand) contributions.

: The recent “crisis” brought about by the collapse of the worldwide commodity coffee market has caused severe economic conditions for coffee producers in developing countries, including those of Central America. As a result, many coffee producers desire to improve the quality and consistency of their product to enter the specialty market. With the ultimate aim of assisting coffee producers in their quality control efforts, this study was designed to determine the feasibility of simple chemical measurements of the fermentation process on remote farms and to assess the potential of these measurements for assisting the producers in control and optimization efforts. Temperature, pH, and the concentrations of glucose, ethanol, and lactic acid were measured throughout the course of 7 coffee mucilage fermentation batches on 4 farms. In each batch, a pattern was observed in which the pH was initially in the range 5.5 to 5.7 and decreased sharply to about 4.6 as fermentation neared completion. Glucose concentration was seen to drop throughout the course of most batches, whereas either ethanol or lactic acid increased sharply near completion. The pH profile may prove useful in predicting the time of fermentation completion and in preventing over‐fermentation of coffee mucilage.

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