Chemical composition and mineral content of goat milk from four indigenous Portuguese breeds in relation to one foreign breed

Raw goat milk samples from Saanen and indigenous Portuguese breeds were analysed for gross composition, minerals and trace elements. Mean results revealed that some distinction could be seen for the Serrana breed. A significant geographical difference (P < 0.05) between Serrana herds was also observed. Generally, milk from Saanen did not differ significantly (P > 0.05) from that of the indigenous Portuguese breeds. Multivariate analysis showed that goat breeds could be divided into two groups, the ones reared mainly inland and those reared towards the coast. Potentially toxic elements were not detected.     

EVALUATION OF PROCESSING, PRESERVATION AND CHEMICAL AND FATTY ACID COMPOSITION OF NILE TILAPIA WASTE

In this experiment, the heads of Nile tilapia were used as a raw material to produce flour through cooking, grinding, drying and sieving processes. The flour obtained was stored for 90 days in a refrigerator and shelf time was monitored by chemical methods (acid number [AN] and thiobarbituric acid [TBA] test), fatty acid composition and microbiological methods. The proximate composition was: moisture (6.01%), ash (19.38%), proteins (38.41%) and total lipids (35.46%). Thirty-six fatty acids were found in the lipidic fraction. The predominant ones were 16:0, 18:1n-9 and 18:2n-6. The fatty acids of the series n-3, 18:3n-3 (alpha-linolenic acid), 18:2n-6 (linolenic acid), 20:5n-3 (eicosapentaenoic acid) and 22:6n-3 (docosahexaenoic acid) were found in smaller proportion. No changes were detected in the flour stored for 90 days as to polyunsaturated fatty acids and microbiological analysis. The AN remained constant up to 60 days of storage and TBA values increased throughout the 90-day storage.

PRACTICAL APPLICATIONS

Waste Nile tilapia heads are not commonly used in human feeding and, therefore, are discarded. In this experiment, Nile tilapia heads were used as a raw material to produce tilapia flour; it was stored in a refrigerator and the shelf time was monitored for 3 months by chemical and microbiological methods. The flour is a caloric food, has high lipid content with omega-3 fatty acids, minerals, proteins and can be used as human feeding.     

Applicability of micro‐FTIR in detecting shale heterogeneity

Samples of Late Devonian/Early Mississippian New Albany Shale from the Illinois Basin, having maturities ranging from early mature to postmature, were analysed using micro‐Fourier transform infrared (FTIR) spectroscopy, ImageJ processing software and scanning electron microscopic X‐ray spectroscopy to explore the distribution, connectivity and chemical composition of organic matter, clay minerals, carbonate minerals and quartz, and to further test the applicability of micro‐FTIR mapping to study shale heterogeneity. Each sample was analysed in planes parallel and perpendicular to the bedding to investigate anisotropy in component distribution, with a possible implication for better understanding anisotropy in porosity and permeability in organic‐matter‐rich shales. Our results show that for low‐maturity samples, organic matter is better connected in the plane parallel to the bedding than in the plane perpendicular to the bedding. Organic matter connectivity decreases with increasing maturity as a result of kerogen transformation. Clay minerals are very well connected in both planes, whereas carbonate minerals are not abundant whilst dominantly isolated in most samples, independent of maturity. This study demonstrates that micro‐FTIR mapping is a valuable tool for studying shale heterogeneity on a micrometre to millimetre scale that becomes even more powerful in combination with scanning electron microscopy techniques, which extend observations to a nanometre scale. However, to obtain meaningful and comparable results, micro‐FTIR mapping requires very careful standardization, precise selection of peak heights/areas and mapping conditions (such as aperture size, scan numbers, resolution, etc.) well suited for the analysed samples.