Date Seed: Rich Source of Antioxidant Phenolics Obtained by Hydrothermal Treatments.

The growing interest in natural compounds is helping to improve the management of agro-industrial by-products such as the date seed as sources of such compounds. In this work, the application of a hydrothermal treatment at 160 and 180 °C for 60 min was studied to achieve the solubilization of its phenolic components and sugars in order to obtain biologically active extracts. The percentage of phenols and total sugars in the final extracts were very similar, at 45 and 25% for the 160 and 180 °C treatments, respectively. The treatment at a higher temperature allowed greater solubilization of other components. The antioxidant activity was measured as free-radical scavenging capacity. For the DPPH• method, expressed as EC50, the results were 0.34 and 0.37 mg/L, the TEAC values for the ABTS• method were 6.61 and 3.28 mg/g dried extract, and the values obtained by the ORAC method were 12.82 and 9.91 mmol Trolox/g dried extract, for 160 and 180 °C, respectively. All these values are higher than those of other plant extracts and extracts obtained using the whole date. Therefore, the date seed is a very important source of phenols, and through thermal and chromatographic processes, it is possible to obtain extracts with high antioxidant activity.

Characterization of Sweet Almond Oil Content of Four European Cultivars (Ferragnes, Ferraduel, Fournat, and Marcona) Recently Introduced in Morocco.

This study concerns the characterization of oil content and quality indices for almond cultivars (Marcona (Mr), Fournat (Fn), Ferragnes (Fg), and Ferraduel (Fd)) recently introduced into marginal agricultural areas in eastern Morocco. These verities are known for their rusticity and late flowering stage. The analyzed almond oils showed low acidity and peroxide values ranging, respectively, from 0.32 to 0.36% and 1.88 to 3.18 meq O2/kg. Fatty acid (FA) profile revealed a predominance of the unsaturated FA represented essentially by the oleic (56.64-64.03%) and linoleic FA (24.57-29.80%). Triacylglycerol (TAG) analysis allowed the determination of eleven species with a remarkable dominance of trioleylglycerol (OOO: 30%) and dioleyllinoleoylglcerol (OOL: 27.25%). Regarding the minor compounds, the results showed that the total phenol content ranges between 85.33 and 141.66 mg/kg. Concerning the tocopherol content, the studied oils showed richness in these secondary metabolites (408.99-491.77 mg/kg) with a dominance of α-tocopherol. In comparison to their homologues in the Mediterranean area, the evaluated almond oils demonstrated a slight superiority in terms of quality, in particular, to those produced in Spain.

Study of the microbial diversity of a panel of Belgian artisanal cheeses associated with challenge studies for Listeria monocytogenes.

High throughput sequencing could become a powerful tool in food safety. This study was the first to investigate artisanal cheeses from Belgium (31 batches) using metagenetics, in relation to Listeria monocytogenes growth data acquired during a previous project. Five cheese types were considered, namely unripened acid-curd cheeses, smear- and mold-ripened soft cheeses, and Gouda-type and Saint-Paulin-type cheeses. Each batch was analyzed in triplicate the first and the last days of storage at 8 °C. Globally, 2697 OTUs belonging to 277 genera and to 15 phyla were identified. Lactococcus was dominant in all types, but Streptococcus was co-dominant in smear-ripened soft cheeses and Saint-Paulin-type cheeses. The dominant population was not always associated with added starter cultures. Bacterial richness and diversity were significantly higher in both types of soft cheeses than in other categories, including particular genera like Prevotella, Faecalibacterium and Hafnia-Obesumbacterium in mold-ripened cheeses and Brevibacterium, Brachybacterium, Microbacterium, Bacteroides, Corynebacterium, Marinilactibacillus, Fusobacterium, Halomonas and Psychrobacter in smear-ripened soft cheeses. A strong correlation was observed between no growth of L. monocytogenes in a smear-ripened cheese and the presence of an unknown Fusobacterium (relative abundance around 10%). This in silico correlation should be confirmed by further experiments in vitro and in situ.

Study of the bacterial profile of raw milk butter, made during a challenge test with Listeria monocytogenes, depending on cream maturation temperature.

Bacteria can play different roles and impart various flavors and characteristics to food. Few studies have described bacterial microbiota of butter. In this study, next-generation sequencing was used to determine bacterial content of raw milk butter, processed during a challenge test, depending on cream maturation temperature and on the presence or not of L. monocytogenes. Two batches were produced. pH and microbiological analyses were conducted during cream maturation and butter storage. DNA was also isolated from all samples for 16S rRNA amplicon sequencing analysis. For butter made from cream matured at 14 °C, a growth potential of L. monocytogenes of - 1.72 log cfu/g was obtained. This value corresponds to the difference between the median of counts at the end of storage and the median of counts at the beginning of storage. This butter (pH value of 4.75 ± 0.04) was characterized by a dominance of Lactococcus. The abundance of Lactococcus was significantly higher in inoculated samples than in control samples (p value < 0.05). Butter made from cream matured at 4 °C (pH value of 6.81 ± 0.01) presented a growth potential of 1.81 log cfu/g. It was characterized by the abundance of psychrotrophic bacteria mainly Pseudomonas. This study demonstrated that cream maturation temperature impacts butter microbiota, affecting thus product's characteristics and its ability to support or not the growth of pathogens like L. monocytogenes.

Proximate Composition, Amino Acid Profile, and Mineral Content of Four Sheep Meats Reared Extensively in Morocco: A Comparative Study.

This study aimed to compare the organoleptic and nutritional quality of four sheep meats produced in Morocco. This comparison was carried out by analyzing the proximate composition, amino acid profile, and mineral content of meat. The majority of the evaluated parameters were influenced by genetic and geographical factors (p < 0.05). The longissimus lumborum muscle had higher a ∗ value in Timahdite and Ouled-Djellal breeds. The highest values of macroelement were recorded in samples of Beni-Guil meat sampled in the Tendrera region (BGT; 1067.3 mg/100 g), while the highest microelement content was registered in Timahdite meat (5.7 mg/100 g). Iron and zinc were the major identified trace elements, while phosphorus and potassium were the most abundant macroelements. The abundant amino acid was glutamic, while cysteine and methionine were least abundant. The higher essential amino acids index (IEAA) was recorded in the Timahdite sheep meat (162.20, 158.71, 161.02, and 159.65, respectively, for Timahdite, BGT, Ouled-Djellal breeds, and Beni-Guil meat sampled in Ain Beni Mathar region). From a nutritional point of view, the studied meats had a good protein and mineral quality, due to their richness in essential amino acids and microelements. The present study provided new insights on the organoleptic quality and the nutritional value of three Moroccan sheep meats reared in outdoor production system.

Determination of the growth potential of Listeria monocytogenes in various types of Belgian artisanal cheeses by challenge tests.

Cheese potentially allowing the growth of Listeria monocytogenes must be free of the pathogen in 25 g before being put on the market, while 100 cfu/g is tolerated when the pathogen is unable to grow. Challenge tests were performed in order to assess the growth potential of L. monocytogenes in at least one batch of 32 Belgian cheese varieties from 32 factories. All varieties were grouped in four categories: unripened acid-curd cheeses, mold-ripened soft cheeses, smear-ripened soft cheeses and ripened semi-hard cheeses. Associated microflora and cheese physicochemical characteristics were also studied. A cocktail of three strains was used to inoculate cheese on the first day of shelf-life, and samples were stored until the end of shelf-life at 7-9 °C. Growth potential was considered as the difference (a) between median contamination at the end and at the beginning of the test or (b) between the highest value at the end of the test and the lowest value at its beginning. L. monocytogenes always decreased in unripened acid-curd cheeses but showed extended growth in 21 out of 25 batches of ripened soft cheese. Contrasting results were obtained for semi-hard cheeses, as important intra- and inter-batch variability was observed. For the latter, the recommended method based on medians to calculate the growth potential led to erroneous food safety considerations, and it should always be advised to focus on absolute levels.

Date Seeds: A Promising Source of Oil with Functional Properties.

The cultivation of the date palm (Phoenix dactylifera L.) is the main activity and source of livelihood for people from arid and semiarid regions of the world. Date production is increasing every year. In addition, pitted date exportation is rising and great amounts of date seeds are produced. This biomass represents a problem for manufacturing companies. At the moment, date seeds are normally discarded or used as animal feed ingredients. However, this co-product can be used for many other applications due to its valuable chemical composition. Oil is one of the most interesting components of the date seed. In fact, date seeds contain 5-13% oil. Date seed oil contains saturated and unsaturated fatty acids with lauric and oleic as the main ones, respectively. Tocopherols, tocotrienols, phytosterols, and phenolic compounds are also present in significant amounts. These phytochemicals confer added value to date seed oil, which could be used for many applications, such as food product formulations, cosmetics, and pharmaceuticals. This review provides up-to-date data on the different extraction techniques and the chemical composition of date seed oils. The applications of date seed oil have also been reviewed.

Smart ulvan films responsive to stimuli of plasticizer and extraction condition in physico-chemical, optical, barrier and mechanical properties.

Smart films were produced with ulvan extracted from the green seaweed Ulva. lactuca at different extraction conditions, by varying the glycerol or sorbitol in specific plasticizer concentration. Chemical composition and molecular weight characteristics of ulvans were carried out by GLC and HPSEC analysis, respectively. Regardless of the extraction procedure, the investigation revealed that ulvans were selected as reproducible and suitable materials of stimuli-responsive due to its peculiar chemical composition and self-aggregation molecular behavior. When using the terminology of stimuli-responsive system, we declare that the physico-chemical, barrier, optical, and mechanical characteristics of ulvan films system are strongly responsive to extraction conditions and to plasticizer type and concentration. As plasticizer concentration increased, thickness, moisture content (MC), water solubility, water vapor permeability (WVP), transparency, elongation at break (EAB), usually UV and visible light protection of ulvan films increased, while, their tensile strength (TS) decreased significantly. The films prepared with glycerol exhibited better solubility, transparency and mechanical properties, than those with sorbitol. However, the films formed with sorbitol had the greatest moisture resistance and more effective vapor, visible and UV light barrier as well as the lowest solubility. The FTIR spectra evidenced the expected outcome of the chemical interaction and miscibility kind between polysaccharides and plasticizers.

Assessment of growth and survival of Listeria monocytogenes in raw milk butter by durability tests.

Butter is a complex matrix characterized by a high fat content. Existing publications on the behavior of Listeria monocytogenes in this type of food reported contrasted results. This study was performed to provide further information and data about raw milk butter's ability to support survival or growth of L. monocytogenes. Durability tests were performed on naturally contaminated samples of raw milk butter with various physico-chemical characteristics. At the end of shelf life, no growth of L. monocytogenes was observed in the studied butters, regardless of their physico-chemical characteristics (pH, aw, water dispersion index and salt concentration) and the initial level of contamination. The number of positive samples and the colony counts of L. monocytogenes were even decreased at the end of the storage period.

Fatty acids, health lipid indices, and cholesterol content of sheep meat of three breeds from Moroccan pastures.

The lipid analysis of commercial lamb's meat, from two main Moroccan production areas Middle Atlas and highlands of eastern Morocco, was conducted. This study concerns the lipid quality of sheep meat from Beni Guil (BG) and Timahdite (Ti) as indigenous breeds and that of the Ouled Djellal (ODj) breed of Algerian origin. To study the effect of the geographical area, the meat samples from the Beni Guil breed were taken in the two main locations of this breed: in the region of Ain Beni Mathar (BGA) and that of Tendrara (BGT). The fatty acid profiles of the sheep meats analyzed showed the following: (i) polyunsaturated fatty acid (PUFA) richness was of 12.87 % and 20.59 % respectively for BGA and BGT breeds; (ii) polyunsaturated  /  saturated fatty acid ratios were ranged between 0.28 to 0.50 respectively for BGA and Ti breed; and (iii) PUFA- n - 3 content was 1.71 % for ODj breed and 2.13 % for BGA. Thus, the PUFA- n - 6   /  PUFA n - 3 ratios range between 4.92 and 9.6 for BGA and Ti sheep meat, respectively. The cholesterol content was 0.08 % and 0.12 % of fresh meat respectively for ODj and BGA. Finally, meats of BGA and ODj have similar thrombogenicity (1.23 and 1.27 respectively) and atherogenicity indices (0.71 and 0.68 respectively). Statistically, these values were significantly higher than those registered for Ti breed (IT: 1.04 and AI: 0.51). In conclusion, from a nutritional point of view, it can be deduced that these meats have an interesting lipid quality due to their richness in desirable fatty acid (UFA  +  C18 : 0).

Effect of low thermal pasteurization in combination with carvacrol on color, antioxidant capacity, phenolic and vitamin C contents of fruit juices.

Mild thermal treatment in combination with natural antimicrobials has been described as an alternative to conventional pasteurization to ensure fruit juices safety. However, to the best of our knowledge, no study has been undertaken to evaluate what could be its effect on their color and nutritional value. This study therefore aimed at assessing how a low thermal pasteurization in combination with carvacrol could affect these parameters, with orange, pineapple, and watermelon juices as selected fruit juices. The experimental design used had levels ranging from 50 to 90°C, 0 to 60 µl/L, and 0 to 40 min for temperature, concentration of carvacrol supplemented, and treatment length, respectively. The only supplementation of fruit juices with carvacrol did not affect their color. In comparison with high thermal pasteurization (>70°C), a combined treatment at mild temperatures (50-70°C) better preserved their color, antioxidant capacity (AOC), and vitamin C content, and increased their total phenolic content (TPC). Globally, carvacrol supplementation had a positive impact on the TPC of thermally treated juices and increased the AOC of treated watermelon juice, which was the lowest of the three fruit juices. Mild heat treatment in combination with natural antimicrobials like carvacrol is therefore an alternative to limit the negative effects of conventional pasteurization on fruit juices quality.

Meat retail conditions within the establishments of Kigali city (Rwanda): bacteriological quality and risk factors for Salmonella occurrence.

Meat constitutes one of the major vehicles for human foodborne infections. This study aimed to assess the retail conditions and to determine the microbiological quality and safety of meat retailed within the establishments of Kigali (Rwanda). A questionnaire survey was carried out in 150 retail outlets to characterise meat retail conditions. Additionally, 270 retail meat samples were analysed for the enumeration of hygiene indicator bacteria (total mesophilic bacteria and Escherichia coli) and for the qualitative detection of Salmonella, using conventional culture methods. The results revealed that beef was the predominant meat sold within the retail premises of Kigali city, while meat from non-bovine animal species was mainly sold in large establishments. Salmonella was detected in 19.6% of all the retailed meat samples evaluated, whereas the mean loads for total mesophilic bacteria and E. coli were 7.3 and 3.5 log cfu/g, respectively. Three factors, namely the temperature conditions of the meat under retail, the cleanability of the used meat cutting boards, and the training of personnel in hygienic meat handling practices, were found to be significantly (p ≤ 0.05) associated with the risk of Salmonella occurrence in the retailed meat. The findings from this study highlight the need for improvements in hygienic meat handling practices, particularly, in small and medium meat retail establishments in Kigali.

Chemical composition, vasorelaxant, antioxidant and antiplatelet effects of essential oil of Artemisia campestris L. from Oriental Morocco.

BACKGROUND: Artemisia campestris L. (Asteraceae) is a medicinal herb traditionally used to treat hypertension and many other diseases. Hence, this study is aimed to analyze the essential oil of A. campestris L (AcEO) and to investigate the antiplatelet, antioxidant effects and the mechanisms of its vasorelaxant effect. METHODS: The chemical composition of AcEO was elucidated using GC/MS analysis. Then, the antioxidant effect was tested on DPPH radical scavenging and on the prevention of ß-carotene bleaching. The antiplatelet effect was performed on the presence of the platelet agonists: thrombin and ADP. The mechanism of action of the vasorelaxant effect was studied by using the cellular blockers specified to explore the involvement of NO/GC pathway and in the presence of calcium channels blockers and potassium channels blockers. RESULTS: AcEO is predominated by the volatiles: spathulenol, ß-eudesmol and p-cymene. The maximal antioxidant effect was obtained with the dose 2 mg/ml of AcEO. The dose 1 mg/ml of AcEO showed a maximum antiplatelet effect of, respectively 49.73% ±9.54 and 48.20% ±8.49 on thrombin and ADP. The vasorelaxation seems not to be mediated via NOS/GC pathway neither via the potassium channels. However, pretreatment with calcium channels blockers attenuated this effect, suggesting that the vasorelaxation is mediated via inhibition of L-type Ca2+ channels and the activation of SERCA pumps of reticulum plasma. CONCLUSION: This study confirms the antioxidant, antiplatelet and vasorelaxant effects of A.campestris L essential oil. However, the antihypertensive use of this oil should be further confirmed by the chemical fractionation and subsequent bio-guided assays.

Cooking Has Variable Effects on the Fermentability in the Large Intestine of the Fraction of Meats, Grain Legumes, and Insects That Is Resistant to Digestion in the Small Intestine in an in Vitro Model of the Pig's Gastrointestinal Tract.

This study aimed to evaluate the fermentation in the large intestine of indigestible dietary protein sources from animal, insect, and plant origin using an in vitro model of the pig's gastrointestinal tract. Protein sources were used raw and after a cooking treatment. Results showed that the category of the ingredient (meats, insects, or grain legumes) exerts a stronger impact on enzymatic digestibility, fermentation patterns, and bacterial metabolites such as short-chain fatty acids (SCFA) and hydrogen sulfide (H2S) than the cooking treatment. The digestibility and the fermentation characteristics of insects were more affected by the cooking procedure than the other categories. Per gram of consumed food, ingredients from animal origin, namely, meats and insects, were associated with fewer fermentation end-products (gas, H2S, SCFA) than ingredients from plant origin, which is related to their higher small intestinal digestibility.

Biology, Flowering and Fruiting of the Cactus Opuntia spp.: A Review and Some Observations on Three Varieties in Morocco

ABSTRACT The cactus is a succulent plant resistant to droughts. According to the recently reviewed classification, cacti belong to the family of Opuntiaceae Desv. (synon. Cactaceae Juss.) with Opuntia Mill. as the typical genus. This genus is economically the most important in the family, as it includes a group of cactus pear plants which play an important role in the agricultural systems of arid and semi-arid regions. Flowering of the cactus pear fruit is an important determinant of the fruit harvesting period. The goal of this paper is to present the physiology of the cactus pear and to explain in detail the biology of its flowering and fruiting processes. This study is also enriched by our observations on the flowering and fruiting of three varieties of cactus pear that we followed for two successive years in southern Morocco.

Antioxidant phenolic extracts obtained from secondary Tunisian date varieties (Phoenix dactylifera L.) by hydrothermal treatments.

Three common non-commercial Tunisian date varieties were treated by two thermal systems, obtaining a liquid fraction which was characterized and its antioxidant capacity determined. The concentration of total phenols in the three varieties (Smeti, Garen Gazel, and Eguwa) was increased by steam explosion treatment up to 5311, 4680, and 3832 mg/kg of fresh dates, and their antioxidant activity up to 62.5, 46.5 and 43.1 mmol Trolox/kg of fresh date, respectively. Both thermal treatments increased the content of phenolic acids. Additionally, a long scale study was carried out in a pilot plant, with steam treatment at 140 °C and 160 °C for 30 min. The liquid phase was extracted and fractionated chromatographically using adsorbent or ionic resins. The phenolic profiles were determined for each fraction, yielding fractions with interesting antioxidant activities with EC50 values of up to 0.08 mg/L or values of TEAC of 0.67 mmol Trolox/g of extract.

Conditioning materials with biomacromolecules: composition of the adlayer and influence on cleanability.

The influence of substrate hydrophobicity and biomacromolecules (dextran, bovine serum albumin - BSA) adsorption on the cleanability of surfaces soiled by spraying aqueous suspensions of quartz particles (10-30µm size), then dried, was investigated using glass and polystyrene as substrates. The cleanability was evaluated using radial flow cell (RFC). The surface composition was determined by X-ray photoelectron spectroscopy (XPS). The interpretation of XPS data allowed the complexity due to the ubiquitous presence of organic contaminants to be coped with, and the surface composition to be expressed in terms of both the amount of adlayer and the mass concentration of adlayer constituents. When soiled with a suspension of particles in water, glass was much less cleanable than polystyrene, which was attributed to its much lower water contact angle, in agreement with previous observations on starch soil. Dextran was easily desorbed and did not affect the cleanability. The presence of BSA at the interface strongly improved the cleanability of glass while the contact angle did not change appreciably. In contrast, soiling polystyrene with quartz particles suspended in a BSA solution instead of water did not change markedly the cleanability, while the contact angle was much lower and the aggregates of soiling particles were more flat. These observations are explained by the major role of capillary forces developed upon drying, which influence the closeness of the contact between the soiling particles and the substrate and, thereby, the adherence of particles. The capillary forces are proportional to the liquid surface tension and depend in a more complex way on contact angles of the particles and of the substrate. The dependence of cleanability on capillary forces, and in particular on the liquid surface tension, is predominant as compared with its dependence on the size and shape of the soiling aggregates, which influence the efficiency of shear forces exerted by the flowing water upon cleaning.

Evaluation of antidiabetic properties of cactus pear seed oil in rats.

CONTEXT: Cactus pear (Opuntia ficus-indica (L.) Mill. (Cactaceae)) is a medicinal plant widely used to treat diabetes. OBJECTIVE: This work investigates the hypoglycemic and antihyperglycemic effect of cactus pear seed oil (CPSO), its mechanism of action, and any toxic effects. MATERIALS AND METHODS: The hypoglycemic effect of CPSO was evaluated in groups of six healthy Wistar rats given 1 or 2 ml kg(-1) orally and compared with groups receiving glibenclamide (2 mg kg(-1)) or water. Glycemia was determined after 30, 60, 120, 240, and 360 min. The antihyperglycemic effect of CPSO was determined in healthy rats and in streptozotocin-induced diabetic rats (STZ); normal rats received 0.8 ml kg(-1) CPSO, while diabetic rats received 1 ml kg(-1) CPSO, their controls received water or 2 mg kg(-1) glibenclamide. For the antihyperglycemic effect evaluation, all the animals were fasted for 16 h before treatment and received glucose orally at 1 g kg(-1) 30 min after treatment; blood was taken after 30, 90, 150, and 210 min. Intestinal glucose absorption was estimated in rat jejunum perfused with a solution containing 5.55 mmol l(-1) glucose. Acute toxicity was determined in albino mice that received oral or intraperitoneal doses of 1, 3, or 5 ml kg(-1) CPSO. RESULTS: CPSO (p.o.) decreased postprandial hyperglycemia (60 min after glucose loading), 40.33% and 16.01%, in healthy and STZ-diabetic glucose-loaded rats, respectively. CPSO, also, significantly decreased intestinal glucose absorption by 25.42%. No adverse effects were seen in mice administered CPSO at up to 5 ml kg(-1). CONCLUSION: CPSO is antihyperglycemic. The effect can be explained partly by inhibition of intestinal glucose absorption.

Physico-chemical mechanisms governing the adherence of starch granules on materials with different hydrophobicities.

The factors influencing the adherence of starch were examined to improve the understanding of the mechanisms affecting soiling and cleanability. Therefore an aqueous suspension of starch granules was sprayed on four model substrates (glass, stainless steel, polystyrene and PTFE) and dried, and the substrates were cleaned using a radial-flow cell. The morphology of the soiled surfaces and the substrate chemical composition were also characterized. By influencing droplet spreading and competition between granule-substrate and granule-granule interfaces regarding the action of capillary forces, substrate wettability affected the shape and compactness of the adhering aggregates, the efficiency of shear forces upon cleaning, and finally the adherence of soiling particles. The rate of drying had an influence explained by the duration left to capillary forces for acting. X-ray photoelectron spectroscopy demonstrated the presence of macromolecules, mainly polysaccharides, which were adsorbed from the liquid phase, or carried by the retracting water film and deposited at the granule-substrate interface. These macromolecules acted as an adhesive joint, the properties of which seemed to be influenced by the detailed history of drying and subsequent exposure to humidity. In summary, the substrate surface energy affects the adherence of starch aggregates by different mechanisms which are all linked together: suspension droplet spreading, action of capillary forces, direct interaction with starch particles and interfacial macromolecules.

Hygiene and cleanability: a focus on surfaces.

Hygiene is a permanent concern for food industries since they must commercialize high quality products in order to comply with the legislation and the expectations of the consumers. The hygienic state of a surface is thus a critical parameter with respect to the performances of the production process and to the final quality of the product. For this reason, cleaning and disinfection are essential. However, the efficiency of the cleaning process will not only depend on the optimization of the process by itself and on the equipment design but also on the characteristics of the soiled surface i.e. mainly its roughness, surface chemical composition, and surface energy. The relation between these parameters and the cleanability are presented here, mainly for food applications. Some examples of existing easy-to-clean and self-cleaning surfaces based on the modification of these surface parameters are also presented.