Archive

Research Area: Nutrient and Bioactive Composition

Effects of processing and storage on almond (Prunus dulcis L.) amandin immunoreactivity.

Su, M., C. Liu, K.H. Roux KH, T.M. Gradziel, S.K. Sathe, 2017. Effects of processing and storage on almond (Prunus dulcis L.) amandin immunoreactivity. Food Res Int. 100(Pt 1):87-95.

A murine monoclonal antibody (mAb)-based enzyme-linked immunosorbent assay (ELISA) was used to assess amandin immunoreactivity in processed and long-term stored almonds. The results demonstrated that amandin immunoreactivity is stable in variously processed almond seeds. Using the ELISA, amandin immunoreactivity could be detected in commercial whole raw and processed (blanched, sliced, dry roasted, and indicated combinations thereof) almond seeds stored for eleven years and eight months, defatted almond seed flours from several almond varieties/hybrids and their borate saline buffer-solubilized protein extracts stored for ten years and seven months, and several almond varieties grown in different California counties (full fat flours and their defatted flour counterparts). Roasting Nonpareil whole full fat almond seeds, full fat flour, and defatted flour at 170°C for 20min each with 2, 5, 10, and 20% w/w corn syrup or sucrose did not prevent amandin detection by ELISA. Similarly, amandin detection in select food matrices spiked with Nonpareil almond protein extract was not inhibited. In conclusion, amandin is a stable target protein for almond detection under the tested processing and storage conditions.

Multiple reaction monitoring profiling to assess compliance with an almond consumption intervention.

Dhillon, J., C.R. Ferreira, T.J.P. Sobreira, R.D. Mattes, 2017. Multiple reaction monitoring profiling to assess compliance with an almond consumption intervention. Curr Dev Nutr. 1(9):e001545. doi: 10.3945/cdn.117.001545.

Background: Almonds are extremely rich sources of lipids and flavonoids, and their consumption is associated with several health benefits. However, there are no analytical methods available to document compliance with prescribed or self-reported chronic almond consumption. Objective: The aim was to use an analytical approach that identifies metabolic profiles associated with long-term almond consumption to ascertain compliance with prescribed consumption. Methods: A multiple reaction monitoring (MRM)–profiling strategy was designed to isolate metabolic changes in erythrocytes after 12 wk of almond consumption. MRM-profiling data acquisition and analysis involve performing separate discovery and screening steps to detect molecular features related to metabolic changes between experimental groups. Samples used for this research were erythrocytes recovered at baseline, after 12 wk of almond consumption (W12almond group), and after 12 wk of a nut-free diet (W12-control group). For the MRM-profiling discovery step, representative samples (pools) of erythrocytes from individuals of all groups were interrogated by precursor ion and neutral loss scan experiments on the basis of previous knowledge of chemical functional groups present in the samples. The outputs of the discovery phase were methods used for the MRM-profiling screening phase to interrogate individual samples on the basis of fast-MRM measurements. In addition, we screened the literature for flavonoids identified in almond skins and included them for individual sample screening. Results: Of the 254 m/z values monitored, 5 ratios and combinations of specific ions with receiver operating characteristic curve AUCs >0.89 provided a sensitivity of 74.2% and a specificity of 90% for blind samples presented in the model. Eight of the 31participants (25.8%) in the W12-almond group and 3 of the 30 (10%) participants in the W12-control group were misclassified by all 5 ratios. Ratios and combinations of specific transitions were mainly related to membrane lipids. Conclusion: The misclassifications observed as a result of ratio performance evaluation may indicate noncompliance as supported by the dietary intake data.

Intramyocellular triacylglycerol accumulation across weight loss strategies; Sub-study of the CENTRAL trial.

Gepner, Y., I. Shelef, D. Schwarzfuchs, N. Cohen, N. Bril, M. Rein, G. Tsaban, H. Zelicha, A. Yaskolka Meir, L. Tene, B. Sarusy, P. Rosen, J.R. Hoffman, J.R. Stout, J. Thiery, U. Ceglarek, M. Stumvoll, M. Blüher, M.J. Stampfer, I. Shai, 2017. Intramyocellular triacylglycerol accumulation across weight loss strategies; Sub-study of the CENTRAL trial. PLoS One. 2017 Nov 30;12(11):e0188431. doi: 10.1371/journal.pone.0188431. eCollection 2017.

BACKGROUND: Intramyocellular triacylglycerol (IMTG) is utilized as metabolic fuel during exercise and is linked to insulin resistance, but the long-term effect of weight loss strategies on IMTG among participants with abdominal fat, remain unclear. METHODS: In an 18-month trial, sedentary participants with abdominal fat/dyslipidemia were randomized to either a low-fat (LF) or Mediterranean/low-carbohydrate (MED/LC) diet (including 28g·day-1 of walnuts). After 6-months, the participants were re-randomized to moderate intense physical activity (PA+) or non-physical activity (PA-). Magnetic resonance imaging (MRI) was used to quantify changes of IMTG, abdominal sub-depots, hepatic and intermuscular fats. RESULTS: Across the 277 participants [86% men, age = 48 years, body-mass-index (BMI) = 31kg/m2, visceral fat = 33%] 86% completed the 18-m trial. At baseline, women had higher IMTG than men (3.4% vs. 2.3%, p<0.001) and increased IMTG was associated with aging and higher BMI, visceral and intermuscular fats, HbA1c%, HDL-c and leptin (p<0.05), but not with intra-hepatic fat. After 18 month of intervention and a -3 kg mean weight loss, participants significantly increased IMTG by 25%, with a distinct effect in the MED/LCPA+ group as compared to the other intervention groups (57% vs. 9.5-18.5%, p<0.05). Changes in IMTG were associated with visceral and intermuscular fat, metabolic syndrome, insulin and leptin (p<0.05 for all), however, these associations did not remain after adjustment for visceral fat changes. CONCLUSIONS: Lifestyle strategies differentially affect IMTG accumulation; combination of exercise with decreased carbohydrate/increased unsaturated fat proportion intake greatly increase IMTG. Our findings suggest that increased IMTG during diet-induced moderate weight loss may not be directly related to cardiometabolic risk.

Changes in the gut microbial communities following addition of walnuts to the diet.

Byerley, L.O., D. Samuelson, E. Blanchard, M. Luo, B.N. Lorenzen, S. Banks, M.A. Ponder, D.A. Welsh, C.M. Taylor, 2017. Changes in the gut microbial communities following addition of walnuts to the diet. J Nutr Biochem. 48:94-102.

Walnuts are rich in omega-3 fatty acids, phytochemicals and antioxidants making them unique compared to other foods. Consuming walnuts has been associated with health benefits including a reduced risk of heart disease and cancer. Dysbiosis of the gut microbiome has been linked to several chronic diseases. One potential mechanism by which walnuts may exert their health benefit is through modifying the gut microbiome. This study identified the changes in the gut microbial communities that occur following the inclusion of walnuts in the diet. Male Fischer 344 rats (n=20) were randomly assigned to one of two diets for as long as 10 weeks: 1) walnut (W), and 2) replacement (R) in which the fat, fiber, and protein in walnuts were matched with corn oil, protein casein, and a cellulose fiber source. Intestinal samples were collected from the descending colon, the DNA isolated, and the V3-V4 hypervariable region of 16S rRNA gene deep sequenced on an Illumina MiSeq for characterization of the gut microbiota. Body weight and food intake did not differ significantly between the two diet groups. The diet groups had distinct microbial communities with animals consuming walnuts displaying significantly greater species diversity. Walnuts increased the abundance of Firmicutes and reduced the abundance of Bacteriodetes. Walnuts enriched the microbiota for probiotic-type bacteria including Lactobacillus, Ruminococcaceae, and Roseburia while significantly reducing Bacteroides and Anaerotruncus. The class Alphaproteobacteria was also reduced. Walnut consumption altered the gut microbial community suggesting a new mechanism by which walnuts may confer their beneficial health effects.

Prebiotic nut compounds and human microbiota.

Lamuel-Raventos, R.M., M.-P. St. Onge, 2017. Prebiotic nut compounds and human microbiota. Critical Reviews in Food Science and Nutrition. 57(14): 3154–3163.

Nut consumption is clearly related to human health outcomes. Its beneficial effects have been mainly attributed to nut fatty acid profiles and content of vegetable protein, fiber, vitamins, minerals, phytosterols and phenolics. However, in this review we focus on the prebiotics properties in humans of the nonbioaccessible material of nuts (polymerized polyphenols and polysaccharides), which provides substrates for the human gut microbiota and on the formation of new bioactive metabolites and the absorption of that may partly explain the health benefits of nut consumption.

In vitro lipolytic, antioxidant and antiinflammatory activities of roasted pistachio kernel and skin constituents.

Grace, M.H., D. Esposito, M.A. Timmers, J. Xiong, G. Yousef, S. Komarnytsky, M.A. Lila, 2016. In vitro lipolytic, antioxidant and antiinflammatory activities of roasted pistachio kernel and skin constituents. Food and Function. doi: 10.1039/c6fo00867d.

A comprehensive phytochemical analysis was conducted on pistachios to identify the differential contributions of skin and kernel phytochemicals to in vitro bioactivity. Qualitative and quantitative analyses of skin and kernel non-polar extracts (SNP and KNP, respectively) indicated that the major components are fatty acids (696.36 and 879.70 mg g−1), phytosterols (16.08 and 4.28 mg g−1), and γ-tocopherol (304.17 and 397.10 µg g−1). Analysis of the skin and kernel polar extracts (SP and KP, respectively) showed that skin accumulated higher levels of phenolic compounds, especially flavan-3-ols, compared to the kernel. An (epi)catechin hexoside was the major component in SP and KP (9.8 mg g−1 and 3.3 mg g−1, respectively). Flavan-3-ols with different degrees of polymerization were detected in SP, but only the monomers were identified in the KP. Quercetin glycosides were the major flavonols present in both SP and KP. Bioassays with 3T3L1 mouse adipocytes demonstrated that all extracts decreased lipid accumulation, with SNP demonstrating the highest activity (17% inhibition). Bioassay guided fractionation of SNP indicated that the lipolytic activity was highest in the fraction consisting of linoleic acid (20%), linolenic acid (10%), and β-sitosterol (50%). Radical scavenging assays indicated that all pistachio extracts significantly inhibited ROS, while SP was the most inhibiting to NO production in LPS-stimulated RAW 264.7 macrophages. Gene expression profiles associated with inflammation (IL6, iNOS, and COX2) were characterized in the LPS-stimulated RAW264.7 macrophages after treatment with pistachio extracts. SP and KP were the most potent to inhibit the expression of COX2. The SNP had the strongest effect in decreasing non-mitochondrial oxidative burst associated with inflammatory response in macrophages.

Food matrix effects of polyphenol bioaccessibility from almond skin during simulated human digestion.

Mandalari, G., M. Vardakou, R. Faulks, C. Bisignano, M. Martorana, A. Smeriglio, D. Trombette, 2016. Food matrix effects of polyphenol bioaccessibility from almond skin during simulated human digestion. Nutrients 568; doi: 10.3390/nu8090568.

Thegoalofthepresentstudywastoquantifytherateandextentofpolyphenolsreleasedin the gastrointestinal tract (GIT) from natural (NS) and blanched (BS) almond skins. A dynamic gastric model of digestion which provides a realistic simulation of the human stomach was used. In order to establish the effect of a food matrix on polyphenols bioaccessibility, NS and BS were either digested in water (WT) or incorporated into home-made biscuits (HB), crisp-bread (CB) and full-fat milk (FM). Phenolic acids were the most bioaccessible class (68.5% release from NS and 64.7% from BS). WT increased the release of flavan-3-ols (p < 0.05) and flavonols (p < 0.05) from NS after gastric plus duodenal digestion, whereas CB and HB were better vehicles for BS. FM lowered the % recovery of polyphenols, the free total phenols and the antioxidant status in the digestion medium, indicating that phenolic compounds could bind protein present in the food matrix. The release of bioactives from almond skins could explain the beneficial effects associated with almond consumption.

Food processing and structure impact the metabolizable energy of almonds.

Gebauer, S.K., J.A. Novotny, G.M. Bornhorst, D.J. Baer, 2016. Food processing and structure impact the metabolizable energy of almonds. Food and Function. 7:4231-4238.

The measured metabolizable energy (ME) of whole almonds has been shown to be less than predicted by Atwater factors. However, data are lacking on the effects of processing (roasting, chopping or grinding) on the ME of almonds. A 5-period randomized, crossover study in healthy individuals (n = 18) was conducted to measure the ME of different forms of almonds (42 g per day), as part of a controlled diet: whole, natural almonds; whole, roasted almonds; chopped almonds; almond butter; and control (0 g per day). After 9 days of adaptation to each diet, participants collected all urine and fecal samples for 9 days. Diets, urine, and feces were analyzed to determine ME. Fracture force and fracture properties of whole and chopped almonds were measured. Measured ME (kcal g−1) of whole natural almonds (4.42), whole roasted almonds (4.86), and chopped almonds (5.04) was significantly lower than predicted with Atwater factors (P < 0.001); ME of almond butter (6.53 kcal g−1) was similar to predicted (P = 0.08). The ME of whole roasted and chopped almonds was lower than almond butter (P < 0.0001). ME of whole natural almonds was lower than whole roasted almonds (P < 0.05). This may be due to lower hardness of whole roasted (298 ± 1.3 N) compared to whole natural almonds (345 ± 1.6 N) (P < 0.05), and to whole natural almonds fracturing into fewer, larger particles, thus inhibiting the release of lipids. Atwater factors overestimate the ME of whole (natural and roasted) and chopped almonds. The amount of calories absorbed from almonds is dependent on the form in which they are consumed.

Walnut phenolic extract and its bioactive compounds suppress colon cancer cell growth by regulating colon cancer stemness.

Lee, J., Y.S. Kim, J. Lee, S.C. Heo, K.L. Lee, S.W. Choi, Y. Kim, 2016. Walnut phenolic extract and its bioactive compounds suppress colon cancer cell growth by regulating colon cancer stemness.Nutrients. 8, 439; doi:10.3390/nu8070439.

Abstract: Walnut has been known for its health benefits, including anti-cardiovascular disease and anti-oxidative properties. However, there is limited evidence elucidating its effects on cancer stem cells (CSCs) which represent a small subset of cancer cells that provide resistance against chemotherapy. This study aimed to evaluate the anti-CSCs potential of walnut phenolic extract (WPE) and its bioactive compounds, including (+)-catechin, chlorogenic acid, ellagic acid, and gallic acid. In the present study, CD133+CD44+ cells were isolated from HCT116 cells using fluorescence-activated cell sorting (FACS) and then treated with WPE. As a result, survival of the CD133+CD44+ HCT116 cells was inhibited and cell differentiation was induced by WPE. In addition, WPE down-regulated the CSC markers, CD133, CD44, DLK1, and Notch1, as well as the β-catenin/p-GSK3β signaling pathway. WPE suppressed the self-renewal capacity of CSCs. Furthermore, the WPE exhibited stronger anti-CSC effects than its individual bioactive compounds. Finally, the WPE inhibited specific CSC markers in primary colon cancer cells isolated from primary colon tumor. These results suggest that WPE can suppress colon cancer by regulating the characteristics of colon CSCs.

 

Walnuts consumed by healthy adults provide less available energy than predicted by the Atwater Factors.

Baer, D., S. Gebauer, J. Novotny, 2016. Walnuts consumed by healthy adults provide less available energy than predicted by the Atwater Factors. J Nutr. 146:1–5.

Background: Previous studies have shown that the metabolizable energy (ME) content (energy available to the body) of certain nuts is less than predicted by the Atwater factors. However, very few nuts have been investigated to date, and no information is available regarding the ME of walnuts. Objective: A study was conducted to determine the ME of walnuts when consumed as part of a typical American diet. Methods: Healthy adults (n = 18; mean age = 53.1 y; body mass index = 28.8 kg/m2) participated in a randomized crossover study with 2 treatment periods (3 wk each). The study was a fully controlled dietary feeding intervention in which the same base diet was consumed during each treatment period; the base diet was unsupplemented during one feeding period and supplemented with 42 g/d walnuts during the other feeding period. Base diet foods were reduced in equal proportions during the walnut period to achieve isocaloric food intake during the 2 periods. After a 9 d diet acclimation period, subjects collected all urine and feces for ;1 wk (as marked by a Brilliant Blue fecal collection marker) for analysis of energy content. Administered diets, walnuts, and fecal and urine samples were subjected to bomb calorimetry, and the resulting data were used to calculate the ME of the walnuts. Results: One 28-g serving of walnuts contained 146 kcal (5.22 kcal/g), 39 kcal/serving less than the value of 185 kcal/ serving (6.61 kcal/g) currently used for food labeling. The ME of the walnuts was 21% less than that predicted by the Atwater factors (P < 0.0001). Conclusion: Consistent with other tree nuts, Atwater factors overestimate the metabolizable energy value of walnuts. These results could help explain the observations that consumers of nuts do not gain excessive weight, and improve the accuracy for food labeling.