Vegetable organogels incorporation in cream cheese products.

Edible oleogels made from rice bran wax (RBW) or ethylcellulose (EC) organogelators in combination with vegetable oils and other non-fat ingredients were used to produce oleogel cream cheese products. Four oleogel cream cheese products, two containing RBW and two with EC, were prepared and compared to control samples including full-fat and fat-free commercial cream cheese samples. Upon compositional analysis, all the oleogel cream cheese (OCC) samples showed approximately a 25% reduction in total fat content in comparison to the full-fat commercial control. More specifically by the replacement of saturated fat with healthier unsaturated fat alternatives, an improved fatty acid profile of cream cheese products was documented. Similar compositional analysis was also performed on a cream cheese sample made with non-gelled vegetable oil. Using a single penetration test and a strain sweep test, oleogel cream cheese samples prepared with RBW displayed comparable hardness, spreadability, and stickiness values to the full-fat commercial control sample. EC OCC samples also showed comparable hardness, spreadability and stickiness values but exhibited reduced adhesiveness values compared to the full-fat control. The successful microstructural incorporation of oleogels into a cream cheese, along with similarities in fat globule size, between OCC samples and commercial controls was confirmed with Confocal Laser Scanning Microscopy. The similarity in microstructure can be accounted for the similarities in textural properties between the OCC samples and the full-fat control. These results provide a thorough characterization of the use of RBW and EC in oleogels and their potential as a healthy alternative to saturated fat in cream cheese applications.

Headspace quantification of pure and aqueous solutions of binary mixtures of key volatile organic compounds in Swiss cheeses using selected ion flow tube mass spectrometry.

RATIONALE: Twelve volatile organic compounds (VOCs) have recently been identified as key compounds in Swiss cheese with split defects. It is important to know how these VOCs interact in binary mixtures and if their behavior changes with concentration in binary mixtures. METHODS: Selected ion flow tube mass spectrometry (SIFT-MS) was used for the headspace analysis of VOCs commonly found in Swiss cheeses. Headspace (H/S) sampling and quantification checks using SIFT-MS and further linear regression analyses were carried out on twelve selected aqueous solutions of VOCs. Five binary mixtures of standard solutions of VOCs were also prepared and the H/S profile of each mixture was analyzed. RESULTS: A very good fit of linearity for the twelve VOCs (95% confidence level) confirms direct proportionality between the H/S and the aqueous concentration of the standard solutions. Henry's Law coefficients were calculated with a high degree of confidence. SIFT-MS analysis of five binary mixtures showed that the more polar compounds reduced the H/S concentration of the less polar compounds, while the addition of a less polar compound increased the H/S concentration of the more polar compound. CONCLUSIONS: In the binary experiment, it was shown that the behavior of a compound in the headspace can be significantly affected by the presence of another compound. Thus, the matrix effect plays a significant role in the behavior of molecules in a mixed solution.

Analysis of selected volatile organic compounds in split and nonsplit swiss cheese samples using selected-ion flow tube mass spectrometry (SIFT-MS).

Splits/cracks are recurring product defects that negatively affect the Swiss cheese industry. Investigations to understand the biophysicochemical aspects of these defects, and thus determine preventive measures against their occurrence, are underway. In this study, selected-ion, flow tube mass spectrometry was employed to determine the volatile organic compound (VOC) profiles present in the headspace of split compared with nonsplit cheeses. Two sampling methodologies were employed: split compared with nonsplit cheese vat pair blocks; and comparison of blind, eye, and split segments within cheese blocks. The variability in VOC profiles was examined to evaluate the potential biochemical pathway chemistry differences within and between cheese samples. VOC profile inhomogeneity was most evident in cheeses between factories. Evaluation of biochemical pathways leading to the formation of key VOCs differentiating the split from the blind and eye segments within factories indicated release of additional carbon dioxide by-product. These results suggest a factory-dependent cause of split formation that could develop from varied fermentation pathways in the blind, eye, and split areas within a cheese block. The variability of VOC profiles within and between factories exhibit varied biochemical fermentation pathways that could conceivably be traced back in the making process to identify parameters responsible for split defect.

Discrimination of Swiss cheese from 5 different factories by high impact volatile organic compound profiles determined by odor activity value using selected ion flow tube mass spectrometry and odor threshold.

Swiss cheese contains more than 200 volatile organic compounds (VOCs). Gas chromatography-mass spectrometry has been utilized for the analysis of volatile compounds in food products; however, it is not sensitive enough to measure VOCs directly in the headspace of a food at low concentrations. Selected ion flow tube mass spectrometry (SIFT-MS) provides a basis for determining the concentrations of VOCs in the head space of the sample in real time at low concentration levels of parts per billion/trillion by volume. Of the Swiss cheese VOCs, relatively few have a major impact on flavor quality. VOCs with odor activity values (OAVs) (concentration/odor threshold) greater than one are considered high-impact flavor compounds. The objective of this study was to utilize SIFT-MS concentrations in conjunction with odor threshold values to determine OAVs thereby identifying high-impact VOCs to use for differentiating Swiss cheese from five factories and identify the factory variability. Seventeen high-impact VOCs were identified for Swiss cheese based on an OAV greater than one in at least 1 of the 5 Swiss cheese factories. Of these, 2,3-butanedione was the only compound with significantly different OAVs in all factories; however, cheese from any pair of factories had multiple statistically different compounds based on OAV. Principal component analysis using soft independent modeling of class analogy statistical differentiation plots, with all of the OAVs, showed differentiation between the 5 factories. Overall, Swiss cheese from different factories was determined to have different OAV profiles utilizing SIFT-MS to determine OAVs of high impact compounds.

Headspace analysis of Italian and New Zealand parmesan cheeses.

UNLABELLED: New Zealand is a leader in the global dairy industry. Milk powder is the principal export product, but there is also a prominent cheese manufacturing industry, catering more for the domestic market. The Selected Ion Flow Tube-Mass Spectrometric (SIFT-MS) technique was used to compare 4 New Zealand cheeses marketed as "parmesan" with 4 Italian Parmigiano Reggiano and Grana Padano cheeses. The cheese headspace was analyzed in real time without any sample preconcentration. Total of 38 volatile compounds in the cheese headspace were monitored with headspace concentrations varying between single digit parts per billion (ppb) to tens of parts per million (ppm). When the results were subjected to multivariate statistical analysis, a clear discrimination was found between the New Zealand "parmesan" and Italian cheeses based solely on the measured concentrations of these volatile compounds. If the volatile compounds used in the analyses were restricted to known odor-active compounds in Parmigiano Reggiano cheese, the ability to discriminate between the cheeses was maintained. The analyses also showed that it was possible to clearly differentiate between the different processing plants in individual countries. Important discriminatory volatiles in the samples tested were butanoic acid and phenylacetaldehyde for discriminating between Italian cheeses and ethyl butyrate, acetaldehyde and methylbutanals between New Zealand cheeses. We conclude that the New Zealand "parmesans" do not provide a good representation of the aroma of Italian "parmesans." PRACTICAL APPLICATION: SIFT-MS has been shown to clearly differentiate both country of origin and the manufacturer of "parmesan" cheeses made in Italy and New Zealand based on differences in volatile organic compounds. Thus this method will have benefit for use in the quality control of "parmesan" and other cheese varieties.

Rapid discrimination and characterization of vanilla bean extracts by attenuated total reflection infrared spectroscopy and selected ion flow tube mass spectrometry.

Vanilla beans have been shown to contain over 200 compounds, which can vary in concentration depending on the region where the beans are harvested. Several compounds including vanillin, p-hydroxybenzaldehyde, guaiacol, and anise alcohol have been found to be important for the aroma profile of vanilla. Our objective was to evaluate the performance of selected ion flow tube mass spectrometry (SIFT-MS) and Fourier-transform infrared (FTIR) spectroscopy for rapid discrimination and characterization of vanilla bean extracts. Vanilla extracts were obtained from different countries including Uganda, Indonesia, Papua New Guinea, Madagascar, and India. Multivariate data analysis (soft independent modeling of class analogy, SIMCA) was utilized to determine the clustering patterns between samples. Both methods provided differentiation between samples for all vanilla bean extracts. FTIR differentiated on the basis of functional groups, whereas the SIFT-MS method provided more specific information about the chemical basis of the differentiation. SIMCA's discriminating power showed that the most important compounds responsible for the differentiation between samples by SIFT-MS were vanillin, anise alcohol, 4-methylguaiacol, p-hydroxybenzaldehyde/trimethylpyrazine, p-cresol/anisole, guaiacol, isovaleric acid, and acetic acid. ATR-IR spectroscopy analysis showed that the classification of samples was related to major bands at 1523, 1573, 1516, 1292, 1774, 1670, 1608, and 1431 cm(-1) , associated with vanillin and vanillin derivatives.

Multicomponent cleaning verification of stainless steel surfaces for the removal of dairy residues using infrared microspectroscopy.

UNLABELLED: The application of infrared microspectroscopy (IRMS) technology, combined with multivariate analysis, was evaluated to develop sensitive and robust methods to assess cleanability of stainless steel surfaces for the removal of dairy food residues. UHT milk samples (skim, 1%, 2%, and whole) were analyzed for total nitrogen (Kjeldahl) and fat (Babcock) contents. The coupons were manually soiled with serially diluted milk samples resulting in soils ranging from 0.1 to 428.1 µg/cm(2) for protein and 0.1 to 374.17 µg/cm(2) for fat, and then autoclaved to simulate a heated equipment surface. Reflectance spectra were collected from stainless steel coupons by using IRMS, and multivariate analysis was used to develop calibration models based on cross-validated partial least squares regression (PLSR). Statistical analysis for the prediction of protein and fat showed a standard error of cross-validation (SECV) of 0.5 and 0.4 µg/cm(2) for prediction of protein and fat, respectively, and correlation coefficients (rVal) > 0.99. To improve the sensitivity, swabbing and concentration steps were used prior to IRMS analysis obtaining SECV of 0.04 and 0.01 µg/cm(2) for the prediction of protein and fat, respectively, and rVal > 0.99. The PLSR models accurately predicted the levels of protein and fat on autoclaved stainless steel coupons soiled with milk. A simple, reliable, and robust protocol based on IRMS and multivariate analysis was developed for multicomponent characterization of stainless steel surfaces that can contribute to more efficient cleaning verification with regard to contamination on surfaces of processing equipment. PRACTICAL APPLICATION: We report the application of Fourier transform infrared microspectroscopy (FTIR) for the validation of CIP cleaning efficiency that would provide a basis for better understanding of the mechanisms involved in the removal of physical soil and food residues from different types of equipment surfaces commonly utilized in the biotech, pharmaceutical, and food industries. Reliable calibration models were generated that showed the ability to predict the amounts of dairy soils on the surface of stainless steel coupons. Including a swabbing step of the coupons before infrared spectral acquisition provided improved sensitivity and reproducibility for multicomponent cleaning verification. Results from this research project would allow designing experiments to rapidly evaluate different materials and finishes, the effects of process variables, the influence of food components, and the development of reliable and robust cleaning validation protocols to ensure the safety and quality of the product.

A promise kept.

This article is largely biographical and relates to my experiences of the past 67 years in research and teaching, both of equal importance in my life. I was fortunate to start at the beginning of the development of instrumental methods of analysis and have eagerly embraced each new methodology as it became available. This paper is dedicated to all those students and colleagues who taught me much and whose efforts are mainly responsible for what has been accomplished in our work with food science and technology. The research focused primarily on trying to find out the "why" behind the problems that food, and especially the dairy products area, encountered over the past 65 years. The teaching has tried to foster thinking and problem solving.

Apoptotic effects of dietary and synthetic sphingolipids in androgen-independent (PC-3) prostate cancer cells.

Stress-induced activation and metabolism of plasma membrane sphingolipids results in intracellular ceramide accumulation and has been shown to induce apoptosis in human prostate cancer cells. This effect has been observed using synthetic ceramide analogs, such as C6-ceramide; however, the effects of naturally-occurring sphingolipids, such as C18-ceramide and sphingomyelin (CerPCho), on apoptosis and prostate cancer cell proliferation have not been examined. The results of the present study demonstrate that natural (CerPCho, C18-ceramide) and synthetic (C6-ceramide) sphingolipids reduced PC-3 cell proliferation by 15 +/- 1.8, 17 +/- 2.5, and 46 +/- 2.1%, respectively (P < 0.05). These reductions in proliferation were due, in part, to increased cellular apoptosis. Treatment of PC-3 cells with CerPCho and C18-ceramide significantly increased apoptosis by 3.0 +/- 0.8 and 3.6 +/- 0.6%, respectively, compared to the untreated control, while the synthetic C6-ceramide significantly increased apoptosis by 55.7 +/- 0.4%. C6-ceramide-induced apoptosis was associated with cell cycle arrest in the G(2)/M phase, decreased extracellular signal-regulated kinase (ERK1/2) signaling and activation of the cell cycle regulatory protein, retinoblastoma (pRb). Treatment of PC-3 cells with C18-ceramide and CerPCho did not alter cell cycle distribution, pRb or ERK1/2 activation. Taken together, these results suggest that natural and synthetic sphingolipids induce apoptosis in PC-3 cells via distinct signaling mechanisms and potencies.

Quantitative assessment of the tetracycline resistance gene pool in cheese samples by real-time TaqMan PCR.

A TaqMan real-time PCR assay was developed to quantify the tetS gene pool present in retail cheeses. This protocol offers a rapid, specific, sensitive, and culture-independent method for assessing antibiotic resistance genes in food samples rich in fats and proteins.