Trends in Grinding of Agroindustrial Products–A Literature review

Background: The milling of food in agro-industrial products has become an operation of high importance at a business, academic and research level. Objective: This article aims to present the results of a literature review on food milling, with the purpose to identify the most recent uses, types of mills, and new grinding trends. Methods: For this, a research equation was made with the keywords "grinding", "milling" and "food" in Scopus, which yielded as results 192 articles, 52 which are directly related to food, were analyzed. Results: Contributions were found in various types of grinding such as cryogenic grinding, nano-scaled grinding, ultrafine and superfine grinding. Conclusion: The authors highlighted the uses of these types of milling in Agro-industrial products such as nutmeg (Myristica fragrans), wheat bran (Triticum spp), ginger (Zingiber officinale) and green tea powder (Camellia sinensis), among others. It is observed that engineering texts dealing with theoretical and analytical food milling operations do not emphasize the new trends found. As a complementary part of this study, eight patents related to cryogenic grinding in food were analyzed, identifying uses of this type of grinding in coffee, lipids, lycopene, proteins, grains, and seeds; Besides, a query was carried out to find out commercial suppliers of cryogenic grinding equipment, in which six companies from China with their equipment were identified.

Discrimination of the Indonesian Roasted Arabica Coffees using 1H NMR-based Metabolomics

In this report, the roasted Arabica coffees obtained from 4 Indonesian regions were analyzed with 1H NMR based-metabolomics. In total, 23 compounds were detected in the coffee 1H NMR spectra. Orthogonal projection to latent structure-discriminant analysis (OPLSDA) model successfully classified metabolites of the coffees based on their origins. S-plots of two-classes partial least square discriminant analysis (PLSDA) models successfully identified discriminant metabolites for every coffee. Chlorogenic acids, trigonelline, arabinoses were found as the discriminant compounds for Preanger-Java coffee. Lipids, acetic acid and lactic acid were discovered as the characteristic metabolites for Gayo-Sumatra coffee. γ-quinide was found as the most important marker for Bajawa-Flores coffee. Meanwhile, Toraja-Sulawesi coffee were characterized with a balance chemical composition indicating its well-balanced taste. The findings revealed the diversity of Indonesian Arabica coffees and shed more light on scientific information of Indonesian coffees.

In Vitro Hypocholesterolemic Effect of Coffee Compounds

(1) Background: Cholesterol bioaccessibility is an indicator of cholesterol that is available for absorption and therefore can be a measure of hypocholesterolemic potential. In this work, the effect of commercial espresso coffee and coffee extracts on cholesterol solubility are studied in an in vitro model composed by glycodeoxycholic bile salt, as a measure of its bioaccessibility. (2) Methods: Polysaccharide extracts from coffees obtained with different extraction conditions were purified by selective precipitation with ethanol, and their sugars content were characterized by GC-FID. Hexane extraction allowed us to obtain the coffee lipids. Espresso coffee samples and extracts were tested regarding their concentration dependence on the solubility of labeled 13C-4 cholesterol by bile salt micelles, using quantitative 13C NMR. (3) Results and Discussion: Espresso coffee and coffee extracts were rich in polysaccharides, mainly arabinogalactans and galactomannans. These polysaccharides decrease cholesterol solubility and, simultaneously, the bile salts’ concentration. Coffee lipid extracts were also found to decrease cholesterol solubility, although not affecting bile salt concentration. (4) Conclusions: Coffee soluble fiber, composed by the arabinogalactans and galactomannans, showed to sequester bile salts from the solution, leading to a decrease in cholesterol bioaccessibility. Coffee lipids also decrease cholesterol bioaccessibility, although the mechanism of action identified is the co-solubilization in the bile salt micelles. The effect of both polysaccharides and lipids showed to be additive, representing the overall effect observed in a typical espresso coffee. The effect of polysaccharides and lipids on cholesterol bioaccessibility should be accounted on the formulation of hypocholesterolemic food ingredients.

The Role of Degreased Vitis Vinifera Seeds on the Oxidation of Coffee Lipids

The objective of this study was to determine the efficiency of degreased antioxidant used to prevent the oxidation of coffee lipids. The coffee samples in mixture with degreased respectively with regular antioxidant were medium roasted and packed in plastic pouches laminated with aluminum foil. All sets of samples were stored for one year at a medium temperature of 22.5�C. The extent of lipid oxidation was followed by determination of peroxide, acidity and refraction values and by chromatographic analyse of fatty acids content.The results show the advantage of using degreased antioxidant towards regular antioxidant to prevent coffee lipid oxidation.

Boiled coffee fails to raise serum cholesterol in hamsters and rats

Boiled coffee contains the lipid compounds cafestol and kahweol, which raise cholesterol strongly in man. These lipids are retained by paper filters. In a search for an animal model for the effect of coffee lipids on serum cholesterol concentrations, we fed hamsters (Mesocvicetus aurutus) and rats on mash diets consisting of a purified base diet and either boiled water, unfiltered boiled coffee or filtered boiled coffee. After a feeding period of 8 weeks there was no statistically significant effect of unfiltered boiled coffee on serum total cholesterol and triacylglycerol concentrations in either the hamsters or the rats. The level of serum cholesterol did respond predictably to the addition of cholesterol and/or saturated fatty acids to the diet. The lack of effect of unfiltered boiled coffee in the hamsters and the rats, when compared with the previously reported activity in humans, could not be explained by dosage, duration of treatment, mode of administration or by insufficient statistical power. It is concluded that hamsters and rats are insensitive to unfiltered boiled coffee and thus are unsuitable models for investigating its hyper- cholesterolaemic effect.