Single versus multiple metabolite quantification of in vitro starch digestion: A comparison for the case of pulse cotyledon cells.

Different quantification methods for in vitro amylolysis were compared for individual chickpea and lentil cotyledon cells (ICC) as a relevant case study. For the first time, much-applied spectrophotometric methods relying on the quantification of certain functional groups (i.e., DNS, GOPOD) were compared to chromatographic quantification of starch metabolites (HPLC-ELSD). The estimated rate constant and linked initial rates of amylolysis were highly correlated for DNS, GOPOD, and HPLC-ELSD. However, absolute amylolysis levels depended on the applied method and sample-specific metabolite formation patterns. Multiresponse modelling was employed to further investigate HPLC-ELSD metabolite formation patterns. This delivered insight into the relative importance of different amylolysis reactions during in vitro digestion of pulse ICC, proving that maltotriose and maltose formation determined the overall amylolysis rate in this case. Multiresponse reaction rate constants of maltotriose and maltose formation were highly correlated to single response amylolysis rate constants (and initial rates) obtained for all three quantification methods.

The genus Boreomysis G.O. Sars, 1869 (Peracarida, Mysida, Mysidae) in western Mexico.

Two species of the genus Boreomysis, B. arctica (Kryer, 1861) and B. californica Ortmann, 1894, were collected in western Mexico. In the eastern Pacific, Boreomysis arctica had previously been recorded from the Bering Sea to southern California. New records in Mexico extend its southernmost distribution limit to 172533 N, off SW Mexico, including samples collected off the west coast of the Baja California Peninsula and the Gulf of California (25 specimens in 12 samples). In the eastern Pacific, B. californica has been reported from Alaska to Peru, with its type locality in the Central Gulf of California. During this study, it was by far the most frequently species collected (343 specimens in 58 samples) off the west coast of the Baja California Peninsula in the Gulf of California, and off SW Mexico (south to 165800 N).

In vitro macronutrient digestibility and mineral bioaccessibility of lentil-based pasta: The influence of cellular intactness.

Recently, pulse ingredients with (partial) cellular intactness are put forward as promising innovative food ingredients with slowed macronutrient digestibility. This study compared cooking quality and nutrient (starch, protein, and mineral) digestibility/bioaccessibility of lentil-based pasta prepared from 100% raw-milled flour, and by substituting 30% of the formulation by isolated cotyledon cell powder or whole precooked powder. Formulation had little effect on cooking properties. Both amylolysis and proteolysis were significantly slowed by incorporating cellular ingredients: towards the end of simulated digestion, amylolysis was lowered by 16-25%, while differences in proteolysis became small. Cellular ingredient incorporation slightly decreased Zn and Mg but did not affect Ca and Fe bioaccessibility, overall yielding a low mineral bioaccessibility comparable to cooked whole pulses. To conclude, lentil-based pasta substituted with cellular ingredients showed improved nutritional properties (i.e., high in digestible protein and slowed amylolysis), with perspectives for the development of different innovative foods with targeted nutritional properties.

Effect of manufacturing conditions on in vitro starch and protein digestibility of (cellular) lentil-based ingredients.

(Cellular) pulse powders are being proposed as ingredients for different foods. However, the effect of manufacturing conditions on the properties of those powders remained unknown. Therefore, this study investigated the effect of specific manufacturing conditions (cooking time, application of cell isolation, and drying method) on the composition, microstructure, and in vitro starch and protein digestibility of lentil powders. Next to powders consisting of isolated cotyledon cells (ICC), this study proposes the production of precooked whole lentil powders (WL), without a cellular isolation step. In a model food system (heat-treated suspension), starch and protein digestion were significantly attenuated for both WL and ICC compared to raw-milled lentil flour. The applied cooking time determined macronutrient digestibility in the powders by (i) affecting the susceptibility of ICC to in vitro digestion, and (ii) determining the microstructural properties of WL. Freeze-dried ICC powder showed a stronger attenuation of amylolysis compared air-dried ICC. This study showed that WL powders have an important potential as innovative food ingredients higher in fiber but lower in starch compared to ICC.

Digestion kinetics of lipids and proteins in plant-based shakes: Impact of processing conditions and resulting structural properties.

In this work, plant-based shakes were prepared (5% oil, 6% protein, 1% lecithin, 88% water) (w/w) using two processing techniques (i) only mixing versus (ii) mixing followed by high pressure homogenisation, as well as two processing sequences (i) adding all ingredients together versus (ii) stepwise addition of ingredients. Shakes only mixed consisted of large, irregular particles (1-100 µm). Eventually, this resulted in a relatively low lipid and protein digestion extent after 2 h of gastric pre-digestion (9% and < 1%, respectively). In contrast, shakes that were subjected to high pressure homogenisation displayed small, homogeneous particles (<10 µm). Besides, lipids and proteins were digested to a high extent in the stomach (40% and 10%, respectively). The small intestinal digestion kinetics indicated a significant impact of proteins on lipid digestion kineticsbutno significant effect of lipids on protein digestion kinetics. The results highlighted the relevance of food processing on macronutrient (micro)structure and further gastrointestinal functionality.

Structural and emulsion stabilizing properties of pectin rich extracts obtained from different botanical sources.

The presented research studied the emulsifying and emulsion stabilizing capacity of pectin samples isolated from different plant origin: apple, carrot, onion and tomato. The acid extracted pectin samples showed distinct structural properties. Specifically, apple pectin showed a high degree of methylesterification (78.41 ± 0.83%), carrot pectin had the lowest concentration of other co-eluted cell wall polymers, onion pectin displayed a bimodal molar mass distribution suggesting two polymer fractions with different molar mass and tomato pectin was characterized by a high protein content (16.48 ± 0.05%). The evaluation of the emulsifying and emulsion stabilizing potential of the pectin samples included investigating their ability to lower the interfacial tension next to a storage stability study of pectin stabilized o/w emulsions. Creaming behavior as well as the evolution of the oil droplet size were thoroughly examined during storage using multiple analytical techniques. Overall, smaller oil droplet sizes were obtained at pH 2.5 compared to pH 6.0 indicating better emulsifying capacity at lower pH. The lowest emulsion stability was observed in emulsions formulated with tomato pectin in which weak flocculation and relatively fast creaming affected emulsion stability. Onion pectin clearly showed the most promising emulsifying and emulsion stabilizing potential. At both pH conditions, emulsions stabilized by the onion pectin sample displayed highly stable oil droplet sizes during the whole storage period. The presence of the two polymer fractions in this sample can play an important role in the observed stability. In future work, it could be evaluated if both fractions contribute to emulsion stability in a synergistic way. In conclusion, this work showed that pectin samples extracted from different plant origin display diverse structural properties resulting in varying emulsifying and emulsion stabilizing potential. Polymer molar mass potentially plays a major role in the structure-function relation.

A new deep-sea species of Epimeria Costa in Hope, 1851 (Amphipoda, Amphilochidea, Epimeriidae) from off southwestern Mexico.

A single ovigerous female specimen of a new species of Epimeria Costa in Hope, 1851 was collected from deep sea, off southwestern Mexico, in the eastern Pacific. Epimeria karamani sp. nov., is most similar to females of E. cora J.L. Barnard, 1971, E. pacifica Gurjanova, 1995 and Epimeria morronei Winfield, Ortiz Hendrickx, 2013. However, it differs from these species by: eyes long and slightly kidney-shaped; pleonite 3 strongly carinate, with dorsal tooth produced and acute; urosomite 1 with a wide mid-dorsal notch and a strong, upright blunt tooth; coxa 3 anterior margin slightly truncate and with two processes marginally; coxa 4 ventral margin linear, with facial granules and simple setae; gnathopods palm with distal bifid setae; telson straight medially, distal margin crenulate and with minute setae. The new species described herein increases the number of Epimeria species from the Pacific Ocean to 14, and from the eastern Pacific to three.

Enzymatic and chemical conversions taking place during in vitro gastric lipid digestion: The effect of emulsion droplet size behavior.

This investigation reports the effect of droplet size behavior on the overall lipolysis profile and molecular lipolysis mechanisms under in vitro gastric conditions. O/W emulsions (5% triolein, 1% sodium taurodeoxycholate) with different initial droplet sizes (fine: 0.58 µm; medium: 1.82 µm; and large: 4.00 µm) were subjected to static in vitro digestion. For the first time, multiple lipolysis products including diolein and monoolein regioisomers were quantified within a single HPLC run. An inverse relation was found between the droplet size and the initial rate and final extent of lipolysis based on the digested triolein. Furthermore, a mechanistic gastric lipolysis model was established based on a reaction scheme including enzymatic and chemical isomerization conversions. The estimated rate of the sn-1/3 hydrolysis was around two- to thirty-fold faster compared to the rates of sn-2 cleavage and isomerization, respectively. These findings resulted in a profound insight in in vitro gastric molecular lipolysis mechanisms.

Redescription of the rare shrimp Heterocarpus nesisi (Burukovsky, 1986 (Crustacea: Caridea: Pandalidae) rediscovered off western Mexico, with the proposal of a new genus.

A rare species of pandalid shrimp, Heterocarpus nesisi Burukovsky, 1986, is rediscovered in deep water off western Mexico. Previous to this capture, this species was known only from the holotype, a mature male captured at 800 m depth, originally described in the genus Heterocarpus and later transferred to Plesionika. A second, unconfirmed record, was provided in 1989: a female captured at 898 m near the southern tip of the Baja California Peninsula. Heterocarpus nesisi is redescribed and appendages are illustrated. The general morphology of this species makes it difficult to fit within Heterocarpus or Plesionika, and a new genus, Heteronika gen. nov., is proposed to accommodate it. Heteronika nesisi is associated with the lower boundary of the Oxygen Minimum Zone occurring off western Baja California.

Redescription of the mysid Petalophthalmus armiger Willemoes-Suhm, 1875 (Crustacea: Mysida: Petalophthalmidae) and distribution off western Mexico.

Specimens of Petalophthalmus armiger Willemoes-Suhm, 1875, were collected off western Mexico during a deep-water survey. Six males and 32 females were obtained from 18 sampling localities in western Mexico. The species is redescribed in detail, including illustrations of body and appendages, and SEM photographs of the mandibles. The new material indicates that P. armiger is widely distributed in the area and more common than previously thought in the eastern Pacific. Samples indicate that P. armiger inhabits water far offshore, where total depth exceeds 1000 m. Due to the lack of discrete samplings in the water column, however, the precise depth interval where P. armiger occurs cannot be defined.

Pectin influences the kinetics of in vitro lipid digestion in oil-in-water emulsions.

Oil-in-water emulsions were prepared with 5% (w/v) carrot-enriched olive oil and stabilized with Tween 80 (TW), phosphatidylcholine (PC), citrus pectin (CP) or a combination of these emulsifiers. Additionally, the methylesterification degree (DM) of citrus pectin was modified, resulting in three different studied pectin structures: CP82, CP38 and CP10. All initial emulsions presented small initial oil droplet sizes and were submitted to an in vitro simulated gastric and small intestinal phase. The latter was executed in a kinetic way to determine the time dependency of the lipolysis reaction, micelle formation and carotenoid bioaccessibility. The results showed that the pectin DM mainly influenced the reaction rate constants, while the emulsifier (combination) determined the extent of lipolysis and carotenoid bioaccessibility. Moreover, a direct relation was observed between the lipolysis reaction and bioaccessibility extent. The presented study showed that targeted emulsion design can be used to tailor lipid digestion kinetics.

Emulsion stability during gastrointestinal conditions effects lipid digestion kinetics.

Oil-in-water emulsions were prepared with carrot- or tomato-enriched olive oil (5%w/v) and stabilized with Tween80 or sucrose esters (0.5%w/v) with different hydrophilic-lipophilic balance (8; 11 or 16). All emulsions had similar initial oil droplet sizes and were submitted to simulated gastrointestinal conditions using a kinetic digestion procedure. Sucrose esters induced an unstable system after gastric conditions leading to coalesced oil droplets, while Tween80 emulsions remained stable. Emulsion particle sizes at the end of the gastric phase were directly associated with the lipolysis kinetics during the intestinal phase. Moreover, a direct relationship was observed between lipolysis and carotenoid micellarisation for all emulsions, and depended mainly on the surfactant structure used. Tween80 emulsions led to a higher lipolysis extent (53-57%) and carotenoid bioaccessibility (17-42%) compared to sucrose ester emulsions (33-52% and 9-27%, respectively). These findings show the importance of the emulsifier structure and emulsion stability during gastrointestinal conditions in modulating lipolysis kinetics.

Lipid digestion, micelle formation and carotenoid bioaccessibility kinetics: Influence of emulsion droplet size.

Carotenoid-enriched oil-in-water emulsions with different droplet sizes (small: d43 0.72µm; medium: d43 1.9µm; large: d43 15.1µm) were subjected to simulated gastrointestinal conditions. The kinetics of lipolysis, micelle formation and carotenoid bioaccessibility were monitored during the intestinal phase. The rates of all three processes increased with decreasing droplet size. The large droplet size emulsion contained undigested oil at the end of digestion, whereas an almost complete hydrolysis was observed for the other two emulsions. The sub-micron emulsion presented a higher conversion of MAGs to FFAs during digestion, which led to a higher concentration of FFAs in the mixed micelles. The incorporation of carotenoids into mixed micelles occurred faster and reached a higher final value for the small droplet size emulsion, leading to final carotenoids bioaccessibility values of around 70%. This work provides valuable information for developing in silico models to simulate the lipid digestibility and carotenoid bioaccessibility.

New records of the deep-sea anemone Phelliactis callicyclus Riemann-Zurneck, 1973 (Cnidaria, Actiniaria, Hormathiidae) from the Gulf of California, Mexico.

Specimens of a deep-sea anemone were observed in photographs and video footage taken with the Remotely Operated Vehicle JASON (WHOI Deep Submergence Laboratory) in the Gulf of California, Mexico, in May 2008. Comparison of our material with photographs and description of this species available in literature indicate that the sea anemones filmed during the JASON survey are most likely to represent Phelliactis callicyclus Riemann-Zurneck, 1973. This species has previously been reported from a locality in the Gulf of California near the present record. During the JASON survey, 28 specimens of P. callicyclus were spotted in 27 locations during six dives. The specimens occurred on angular rock outcrops along the escarpments of the transform faults of the Gulf of California, between depths of 993-2543 m and at temperatures ranging from 2.3 to 4.5°C. Based on these new records, Phelliactis callicyclus appears to be widely spread in the Gulf of California.

Two species of the deep-water shrimp genus Nematocarcinus A. Milne-Edwards, 1881 (Crustacea, Decapoda, Caridea, Nematocarcinidae) from the Mexican Pacific.

The distribution of two species of the deep-water shrimp genus Nematocarcinus A. Milne-Edwards, 1881, occurring off the west coast of Mexico is analyzed based on a large series of recently collected material. Nematocarcinus faxoni Burukovsky, 2000, is by far the most common and abundant species in the area and it is distributed throughout the central and southern Gulf of California and off the entire Baja California Peninsula south to 17º10'15"N. Based on characteristics observed in the new samples and in the type material, N. agassizii Faxon, 1893, is reinstalled as a valid species, and no longer considered a junior of N. gracilipes A. Milne-Edwards, 1881, as proposed by Cardoso & Burukovsky (2014). Along the Pacific coast of Mexico, N. agassizii exhibits a more restricted distribution and it was collected only off the Baja California Peninsula. Previous records of this species in the Gulf of California, where N. faxoni was the only representative of the genus captured during this survey, are considered doubtful.

L-ascorbic acid improves the serum folate response to an oral dose of [6S]-5-methyltetrahydrofolic acid in healthy men.

OBJECTIVE: To investigate the effect of simultaneous administration of [6S]-5-methyltetrahydrofolic acid ([6S]-5-CH(3)H(4)PteGlu) with L-ascorbic acid (L-AA) on serum folate concentrations in healthy male subjects. SUBJECTS AND METHODS: A total of nine healthy male volunteers were recruited. Serum folate concentrations were measured before and up to 8 h after administration of each treatment (1) placebo, (2) 343 microg [6S]-5-CH(3)H(4)PteGlu), (3) 343 microg [6S]-5-CH(3)H(4)PteGlu) with 289.4 mg L-AA and (4) 343 microg [6S]-5-CH(3)H(4)PteGlu) with 973.8 mg L-AA (n=10 samples per treatment). RESULTS: Serum folate concentrations significantly increased compared with baseline values, starting from 30 min after [6S]-5-CH(3)H(4)PteGlu administration and remained significantly higher than baseline values during the first 6 h for treatments 3 and 4, and during the first 4 h for treatment 2. Maximal serum folate responses were observed between 0.5 and 1.5 h after [6S]-5-CH(3)H(4)PteGlu consumption and significantly differed between treatments 2 and 4 (P<0.05). When [6S]-5-CH(3)H(4)PteGlu was concurrently administered with 289.4 or 973.8 mg L-AA, the total serum folate response, calculated as the area under the curve (AUC), was significantly improved (46.5+/-4.0 and 53.0+/-4.0 vs 34.3+/-3.8 h nmol/l, P<0.05). No significant difference in AUC was found between the 289.4 and the 973.8 mg L-AA treatments. CONCLUSIONS: Administration of a physiological dose of [6S]-5-CH(3)H(4)PteGlu with L-AA significantly improved the measured serum folate response in folate saturated healthy men.

Purified tomato polygalacturonase activity during thermal and high-pressure treatment.

Extracted tomato polygalacturonase was purified by cation-exchange chromatography (and gel filtration) and characterized for molar mass, isoelectric point, as well as optimal pH for polygalacturonase activity. The enzymatic reaction of purified tomato polygalacturonase on polygalacturonic acid as substrate was investigated during a combined high-pressure/temperature treatment in a temperature range of 25 degrees to 80 degrees C and in a pressure range of 0.1 to 500 MPa at pH 4.4 (the pH of tomato-based products). The optimal temperature for initial tomato polygalacturonase activity in the presence of polygalacturonic acid at atmospheric pressure is about 55 degrees to 60 degrees C. The optimal temperature for initial tomato polygalacturonase activity during processing shifted to lower values at elevated pressure as compared with atmospheric pressure, and the catalytic activity of pure tomato polygalacturonase decreased with increasing pressure, which was mostly pronounced at higher temperatures. The elution profiles of the degradation products on high-performance anion-exchange chromatography indicated that for both thermal and high-pressure treatment all oligomers were present in very small amounts in the initial stage of polygalacturonase activity. The amounts of monomer and small oligomers increased with increasing incubation times, whereas the amount of larger oligomers decreased due to further degradation.

Formation kinetics of hydroxymethylfurfural, lactulose and furosine in milk heated under isothermal and non-isothermal conditions.

A detailed kinetic study of hydroxymethylfurfural, lactulose and furosine formation was performed upon heating milk at temperatures between 90 degrees C and 140 degrees C. In case of prolonged heating, formation kinetics could be described by a fractional conversion model. Considering only the first phase of the model, kinetics could be simplified to a pseudo-zero order model. A first assessment of kinetic parameters was made by isothermal experiments. Data were analysed using both a 2-step linear and a 1-step non-linear regression method. Only for furosine, did the global 1-step regression approach seem to give better results than the individual 2-step regression approach. Next, the estimated parameters k(ref) and Ea were re-evaluated under non-isothermal conditions by subjecting milk to a time variable temperature profile. Given the complexity of Maillard reaction, it seemed better to estimate kinetic parameters under non-isothermal conditions when using a simplified model. Formation of hydroxymethylfurfural, lactulose and furosine was characterized by an Ea value of 90.2 kJ/mol (k(110 degrees C) = 1.2 micromol/l, min), 99.1 kJ/mol (k(110 degrees C) = 51.5 mg/l, min) and 88.7 kJ/mol (k(110 degrees C) = 16.3 mg/100 g protein, min) respectively. Additionally, 90% joint confidence regions were constructed in order to obtain an accurate representation of the statistical confidence associated with the simultaneously estimated parameters.