Diagnosing the cage of covariance to increase understanding and robustness of spectroscopic calibration models.

When vibrational spectroscopy is used for quantification purposes, multivariate analysis is often used to extract information from covariances between the spectra and any given reference values. In complex samples, there is a high risk that the constituents covary with each other. In such scenarios many methods may confuse the analytes and use signal from several analytes, rather than just the analyte of interest. While this allows the method to use more signal, and thus have a better effective signal-to-noise ratio, it also makes them less robust to changes to the chemical composition in the samples. This effect has been termed the cage of covariance. In order to avoid cage of covariance to affect predictive performances, it is highly important to have simple diagnostic tools to analyze and review this effect. Therefore, in the present paper, a systematic overview of tools for diagnosing and quantifying the cage of covariance in spectroscopic calibration models is provided. A collection of previously published methods with some expansions is provided, as well as two completely new tools: covariance ratio and virtual spiking. Practical applications of the tools on three different datasets are also shown.

The role of biospectroscopy and chemometrics as enabling technologies for upcycling of raw materials from the food industry.

It is important to utilize the entire animal in meat and fish production to ensure sustainability. Rest raw materials, such as bones, heads, trimmings, and skin, contain essential nutrients that can be transformed into high-value products. Enzymatic protein hydrolysis (EPH) is a bioprocess that can upcycle these materials to create valuable proteins and fats. This paper focuses on the role of spectroscopy and chemometrics in characterizing the quality of the resulting protein product and understanding how raw material quality and processing affect it. The article presents recent developments in chemical characterisation and process modelling, with a focus on rest raw materials from poultry and salmon production. Even if some of the technology is relatively mature and implemented in many laboratories and industries, there are still open challenges and research questions. The main challenges are related to the transition of technology and insights from laboratory to industrial scale, and the link between peptide composition and critical product quality attributes.

In-Line Near-Infrared Spectroscopy Gives Rapid and Precise Assessment of Product Quality and Reveals Unknown Sources of Variation-A Case Study from Commercial Cheese Production.

Quality testing in the food industry is usually performed by manual sampling and at/off-line laboratory analysis, which is labor intensive, time consuming, and may suffer from sampling bias. For many quality attributes such as fat, water and protein, in-line near-infrared spectroscopy (NIRS) is a viable alternative to grab sampling. The aim of this paper is to document some of the benefits of in-line measurements at the industrial scale, including higher precision of batch estimates and improved process understanding. Specifically, we show how the decomposition of continuous measurements in the frequency domain, using power spectral density (PSD), may give a useful view of the process and serve as a diagnostic tool. The results are based on a case regarding the large-scale production of Gouda-type cheese, where in-line NIRS was implemented to replace traditional laboratory measurements. In conclusion, the PSD of in-line NIR predictions revealed unknown sources of variation in the process that could not have been discovered using grab sampling. PSD also gave the dairy more reliable data on key quality attributes, and laid the foundation for future improvements.

In-Line Estimation of Fat Marbling in Whole Beef Striploins (Longissimus lumborum) by NIR Hyperspectral Imaging. A Closer Look at the Role of Myoglobin.

Fat marbling, the amount, and distribution of intramuscular fat, is an important quality trait for beef loin (Longissimus lumborum) and is closely connected to sensory properties such as tenderness, juiciness, and flavor. For meat producers, it would be of value to grade and sort whole loins according to marbling on the production line. The main goal of this study was to evaluate high-speed NIR hyperspectral imaging in interaction mode (760-1047 nm) for in-line measurement of sensory assessed marbling in both intact loins and loin slices. The NIR system was calibrated based on 28 whole striploins and 412 slices. Marbling scores were assessed for all slices on a scale from 1 to 9 by a trained sensory panel. The calibrated NIR system was tested for in-line measurements on 30 loins and 60 slices at a commercial meat producer. Satisfactory accuracy for prediction of marbling was obtained by partial least squares regression for both slices and whole loins (R2 = 0.81 & 0.82, RMSEP = 0.95 & 0.88, respectively). The concentration of myoglobin in the meat and its state of oxygenation has a strong impact on the NIR spectra and can give deviations in the estimated marbling scores. This must be carefully considered in industrial implementation.

Improved microbial and sensory quality of chicken meat by treatment with lactic acid, organic acid salts and modified atmosphere packaging.

Microbial contamination and growth play important roles in spoilage and quality loss of raw poultry products. We evaluated the suitability of three commercially available organic acid based antimicrobial compounds, Purac FCC80 (l-lactic acid), Verdad N6 (buffered vinegar fermentate) and Provian K (blend of potassium acetate and diacetate) to prevent growth of the innate microbiota, reduce spoilage and enhance the sensory quality of raw chicken under vacuum, high CO2 (60/40% CO2/N2), and high O2 (75/25% O2/CO2) modified atmosphere (MA) storage conditions. Solutions were applied warm (50 °C) or cold (4 °C) to reflect treatments prior to (Prechill) or after (Postchill) cooling of chicken carcasses, respectively. Single postchill treatments of raw chicken wings with 5% Verdad N6 or Provian K solutions and MA storage enabled complete growth inhibition during the first seven days of storage before growth resumed. Enhanced bacterial control was obtained by combining Prechill lactic acid and Postchill Verdad N6 or Provian K treatments which indicated initial reductions up to 1.1 log and where total bacterial increase after 20 days storage was limited to 1.8-2.1 log. Antibacterial effects were dependent on the concentration of the inhibiting salts used, pH and the storage conditions. Bacterial community analyses showed increased relative levels of Gram-positive bacteria and with reductions of potential spoilage organisms in samples treated with the organic acid salts Verdad N6 and Provian K. Sensory analyses of raw, treated wings showed prominent lower scores in several spoilage associated odour attributes when compared with untreated chicken wings after 13 days storage. For heat-treated chicken, only minor differences for 22 tested attributes were detected between seven antimicrobial treatments and untreated control chicken. Immersion in commercially available organic acid/salt solutions combined with MA storage can reduce bacterial levels, improve microbial and sensory quality, and potentially improve shelf life and reduce food waste of chicken products.

Improved control of Listeria monocytogenes during storage of raw salmon by treatment with the fermentate Verdad N6 and nisin.

Fresh Atlantic salmon (Salmo salar) represents a healthy, nutritious food with global distribution and increasing consumption and economic value. Contaminating Listeria monocytogenes in fresh salmon represents a health hazard to consumers, is linked to extensive product recalls and is a major challenge for salmon processors. Verdad N6, a commercially available buffered vinegar, was evaluated as a treatment for raw salmon fillets either alone or in combination with the antimicrobial peptide nisin, with regard to anti-listerial effects under processing and storage, and influence on sensory quality and background microbiota. Salmon fillets were surface contaminated with L. monocytogenes and immersed in solutions of Verdad N6 or treated with nisin or a combination of these two treatments. Levels of L. monocytogenes were determined during vacuum-pack refrigerated storage. The use of Verdad N6 resulted in increased lag times and substantially reduced growth of L. monocytogenes. The inhibitory effects were dependent on Verdad N6 levels, immersion time, and storage time and temperature. A 5 s immersion in 10% Verdad N6 solution at 4 °C reduced growth of L. monocytogenes from log 2.8 to log 1 after 12 days of storage. Nisin (0.2-1 ppm) had listericidal effects up to 1 log but did not inhibit regrowth when used alone. Appropriate combinations of Verdad N6 and nisin led to L. monocytogenes levels no higher after 12 days of storage than the initial levels. The inhibitory effects were markedly lower at 7 °C than at 4 °C. Salmon with Verdad N6 showed reduced levels of total counts during storage indicating a longer shelf-life, and a shift in the dominating bacteria with reduced and increased relative levels of Enterobacteriaceae and lactic acid bacteria, respectively. Sensory analyses of raw and cooked Verdad N6 treated a non-treated salmon resulted in small differences. In summary, Verdad N6 is an option for production of high-quality raw salmon with increased shelf-life and enhanced food safety through its Listeria inhibiting effects. The application of Verdad N6 in combination with nisin treatment can further reduce the listeria-risks of these products.

Distribution of cerebral atherosclerosis by geographic location, race, and sex

The cerebral arteries (common carotid, internal carotid, vertebral, middle cerebral, and basilar arteries) were examined from 1547 autopsied persons in five countries (Norway, Guatemala, United States, Jamaica, and Chile). Subgroups comparisons were made using a basal group of cases from which were excluded all persons with coronary heart disease, peripheral arterial disease, other atherosclerotic complication, hypertension, and diabetes. The prevalence and mean extent of atherosclerotic lesions increase in each succeeding age group. Lesions appear to develop later in life in the cerebral arteries than in the aorta and the cerebral arteries than in the aorta and the coronary arteries. Men have more raised atherosclerotic lesions than women. The mean extent of fatty streaks in the cartoid arteries does not differ among age groups from 35 to 69 years of age, nor does it differ among location-race groups. The mean extent of raised atherosclerotic lesions in the carotid arteries increases in each succeeding age group after 35 years of age, and differs among location-race groups.The pattern of development of atherosclerosis in the carotid arteries follows that of the aorta. Fatty streaks appear in the intracranial and vertebral arteries much later in life than they do in the carotid arteries.The mean extent of both fatty streaks and raised lesions increases in each succeeding age group after 35 years of age, and the average involvement of both types of lesions differs among location-race groups. The pattern of development of atherosclerosis in the vertebral and intracranial arteries follows that of the coronary arteries. When location-race groups are ranked by extent of cerebral atherosclerosis, they rank in approximately the same order as when they are ranked by aortic and coronary atherosclerosis. (AU)

Atherosclerosis in persons with selected diseases

Comparison has been made of measures of coronary and aortic atherosclerosis in autopsied persons having five selected diseases (lung cancer,stomach cancer, other cancer, cirrhosis of the liver, and tuberculosis) with similar measures in control cases. There appears to be a slight but not significant tendency for lung cancer to be associated with more severe atherosclerosis within age-location-race subgroups. The tendency is strongest in the abdominal aorta. None of the other four diseases appears to be associated with increased or decreased severity of atherosclerosis in comparison with the control groups.(AU)

Distribution of coronary and aortic atherosclerosis by geographic location, race, and sex

Cooperating pathologists in different countries collected 23,207 sets of coronary arteries and aortae, according to a standard protocol. A central laboratry staff stained the arteries with Sudan IV, and a team of pathologists graded the atherosclerotic lesions. A basal group of cases which died from accidents, infections, cancer, and selected miscellaneous causes was extracted in order to compare atherosclerosis among the different geographic, racial, and sex subgroups. Even the most homogeneous subgroups (same location, sex, age, and race) vary greatly in extent of advanced atherosclerotic lesions. The 19 location-race groups differ significantly in extent of raised lesions. The abdominal aorta and the left anterior descending coronary artery have more atherosclerosis than other arteries. Within most location-race groups, coronary arteries of men have more raised lesions than the coronary arteries of women. Aortae of men in some groups have slightly more, and in other groups slightly less raised lesions than the aortae of women. Negro groups show little or no sex difference in either the coronary arteries or the aorta. Ranking of the 19 location-race groups by raised atherosclerotic lesions is similar, regardless of lesion measure (fatty streaks excepted), sex, artery, or age group. New Orleans white and the Oslo group rank highest; Bogota, Sao Paulo Negro, Guatemala, and Durban Bantu groups rank lowest. With few exceptions, ranking these groups by raised lesions corresponds closely with ranking them by coronary heart disease mortality rate. (AU)