Influence of Cooking Conditions on Carotenoid Content and Stability in Porridges Prepared from High-Carotenoid Maize

Maize is a staple food crop in many developing countries, hence becoming an attractive target for biofortification programs toward populations at risk of micronutrient deficiencies. A South African white endosperm maize inbred line was engineered with a carotenogenic mini-pathway to generate high-carotenoid maize, which accumulates β-carotene, lutein and zeaxanthin. As maize porridge is a traditional meal for poor populations in sub-Saharan African countries, high-carotenoid maize was used as raw material to prepare different maize meals. The objective of this work was to assess the impact of popular home-cooking techniques and different cooking parameters (temperature, time and pH) on the final carotenoid content in the cooked product, using a spectrophotometric technique based on the mean absorption of carotenoids at 450 nm. Carotenoid levels were not only preserved, but also enhanced in high-carotenoid maize porridges. The carotenoid content was increased when temperatures ≤95 °C were combined with short cooking times (10–60 min). The most optimum thermal treatment was 75 °C/10 min. When treated under those conditions at pH 5, high-carotenoid maize porridges doubled the initial carotenoid content up to 88 μg/g dry weight. Regarding to cooking techniques, the highest carotenoid content was found when unfermented thin porridges were prepared (51 μg/g dry weight of high-carotenoid maize porridge). We conclude that high-carotenoid maize may contribute to enhance the dietary status of rural populations who depend on maize as a staple food.     

Biological utilization of vegetable peas: Effect of cooking and varietal differences

The flour of raw as well as cooked vegetable pea cultivars (Arkal and Bonneville) was used for biological evaluation of their protein quality. Cooking did not have a significant influence on the food intake. There were some differences in the food as well as protein intake and gain in body weights of rats when fed uncooked or cooked pea flour diets. Varietal differences did not seem to influence on apparent digestibility, true digestibility, biological value, net protein utilization and utilisable protein but cooking brought a significant (p<0.05) improvement in all of above mentioned parameters. Varietal differences as well as cooking exhibited no influence or serum protein concentration.     

Nutrient composition and biological evaluation of mesta (Hibiscus sabdariffa) seeds

Two varieties of mesta (Hibiscus sabdariffa) seeds were analysed for their proximate composition. Their protein (18.8–22.3%), fat (19.1–22.8%) and dietary fiber (39.5–42.6%) contents were found to be high. The seeds were found to be a good source of minerals like phosphorus, magnesium and calcium. Their lysine and tryptophan contents were also high. Sulphur containing amino acids were limiting in this seed protein and the chemical score of mesta seed protein was 40 and 57 for AMV-2 and Bhimili-1 varieties respectively. Mesta seed oil is rich in unsaturated fatty acids (70%), of which linoleic acid constituted 44%. Weanling rats were fed with 10% mesta seed protein before and after cooking for 4 weeks. Food intake of animals receiving raw mesta seed diets was significantly lower than those receiving cooked mesta seed diets as well as the casein control diet. Protein and dry matter digestibilities of raw and cooked mesta seed diets were lower than that of casein control diet. Cooking improved the food intake, gain in body weight, dry matter and protein digestibility of mesta seed diets. PER and NPU of cooked mesta seed diets were significantly higher than the corresponding raw diets. These results indicate that cooked mesta seed protein is of relatively good quality.     

Effects of altitude above sea level on the cooking time and nutritional value of common beans

The present study was conducted with the objective to determine the effects of altitude above sea level, on the cooking time and nutritional value of common black beans (Phaseolus vulgaris). Three 100 g samples of theOstua variety were cooked at 8 individual locations, ranging in altitude from 0 to 2256 meters, in Guatemala, to establish water uptake and cooking time. The cooked samples were separated into cooked beans and cooking broth for chemical analysis. This included moisture, protein, lysine, tannins, total and enzyme susceptible starch, and fiber fractionation. The cooking liquor was analyzed for total solids, moisture, protein, ash and K. A 1200 g sample was cooked for the cooking time established previously, for biological testing of nutritional value,which included Net Protein Ratio (NPR), Protein Effciency Ratio (PER), and protein digestibility. Altitude influenced cooking time which increased from 78 min at 0 m, to 264 min at 2256 m. Final moisture content in the cooked bean was similar at all altitudes and there was a tendency to yield smaller amounts of solids in the cooking broth at higher altitudes. The increase in cooking time was significant. Bean water uptake at all times was significantly slower and smaller at ambient T, as compared to water uptake at boiling T, at all altitudes. Protein and lysine content were not affected by altitude, however, tannin and catechin were lower in cooked samples, as compared to the raw material. Altitude did not affect the content of these substances. Total starch and total sugars were higher in the raw sample, as compared to the cooked samples, but there was no effect of altitude. Enzyme susceptible starch (ESS) was lower in the raw sample as compared to the cooked samples, which contained similar amounts with respect to altitude. No change was observed in fiber fractions of the cooked beans. Likewise, the composition of the cooking broth was very similar between cooking locations. There was a small tendency to a lower protein quality, with respect to altitude, the effect of which was more obvious in the apparent protein digestibility values. Undercooking or overcooking at one location influenced protein quality values. The extended cooking time of beans at high altitudes, has important economic and environmental implications, since significant amounts of wood have to be used.     

Effect of Spinacia oleraceae L. and Perilla frutescens L. on Antioxidants and Lipid Peroxidation in an Intervention Study in Healthy Individuals

Daily consumption of fruits and vegetables is frequently recommended to prevent several diseases. This health-promoting effect is considered to be in part due to the antioxidant content of fruits and vegetables and their ability to decrease oxidative stress. To investigate whether the ingestion of preparations from spinach or perilla, two carotenoid-rich leafy vegetables, is followed by an increase in carotenoid concentration and/or affects parameters of oxidative stress in human blood plasma. 12 healthy volunteers ingested a perilla- or spinach preparation for 10 days (5 mg lutein/d). We quantified antioxidant levels in plasma, kinetics of lipid peroxidation, MDA concentration, and total antioxidative capacity of plasma. We observed a significant increase in lutein content and a moderate increase (n.s.) in β-carotene content in human blood plasma after consumption of spinach or perilla. The markers of lipid peroxidation tended to decrease, but no influence on antioxidative capacity of plasma could be detected. The high lutein content of perilla caused a more pronounced increase of lutein compared to spinach. Both vegetables seem to be able to influence lipid peroxidation in a beneficial manner.     

Carotenoid composition and antioxidant activity of tortillas elaborated from pigmented maize landrace by traditional nixtamalization or lime cooking extrusion process

Mexican pigmented maize (Zea mays L.) landrace kernels have been scantily evaluated regarding potential as functional food. In this study, eight Mexican pigmented (yellow and red) maize accessions of Tuxpeño, Tabloncillo and Chapalote landraces collected in the northwestern region of Mexico were processed into tortilla to determinate carotenoid profiles, as well as their Oxygen Radical Absorbance Capacity for Lipophilic extract (ORAC-L). The total carotenoid content ranged from 3.66 to 5.56 mg LE/kg DW in the yellow maize and from 1.49 to 3.49 mg LE/kg DW in the red maize among all raw genotypes. Lutein and zeaxanthin were major carotenoids in all pigmented maize, accounting for ∼85% of total carotenoids. The traditional nixtamalization and lime-cooking extrusion process significantly (p < 0.05) decrease total carotenoid and ORAC-L assays when compared to raw kernels. Traditional tortillas retained among 72.0–87.6% and 65.1–78.8% of total carotenoids and ORAC-L levels respectively, compared to 68.8–79.5% and 60.3–75.5% assayed in extruded tortillas. Interestingly, traditional and extruded tortillas maintained more 72.7 and 60%, respectively; of the lutein concentration associated with raw grains. Our results suggest that yellow maize landrace could be considered for the elaboration of nixtamalized food products with nutraceutical potential.     

Carotenoid Content of Commonly Consumed Herbs and Assessment of Their Bioaccessibility Using an In Vitro Digestion Model

Herbs are a rich source of bioactive phytochemicals such as carotenoids, which are known to exert various positive biological effects. However, there is very limited information in the literature regarding the content and bioavailability of carotenoids from commonly consumed herbs. Therefore, the objectives of the present study were first, to determine the carotenoid content of eight herbs namely basil (Ocimum basilicum), coriander (Coriandrum sativum), dill (Anethum graveolens), mint (Metha L.), parsley (Petroselinum crispum), rosemary (Rosmarinus officinalis), sage (Salvia officinalis), and tarragon (Artemisia dracunculus L.); and second, to assess carotenoid bioaccessibility from these herbs using a simulated human in vitro digestion model. Carotenoid bioaccessibility is defined as the amount of carotenoids transferred to micelles after digestion when compared with the original amount present in the food. The content of individual carotenoids varied significantly among the herbs tested. Carotenoid bioaccessibility varied from 0 to 42.8%. Basil and coriander, and their respective micelles, contained the highest levels of β-carotene, β-cryptoxanthin, and lutein + zeaxanthin. Our findings show that herbs are rich sources of carotenoids and that these foods can significantly contribute to the intake of bioaccessible carotenoids.     

Effect of domestic processing on zinc bioavailability from ricebean (Vigna umbellata) diets

The effects of various processing methods viz. pressure cooking with soaking, sprouting (48 h), sprouting and pressure cooking, dehulling, and pressure cooking of the dehulled legume on the bioavailability of zinc were studied. The total zinc content varied from 3.28 to 3.37%; the highestbeing in raw ricebeans and the lowest being in dehulled, soaked and pressure cooked, and sprouted and pressure cooked ricebeans, respectively. The soluble zinc content was highest for dehulled soaked and pressure cooked ricebeans (28.2%) and lowest for raw ricebeans (16.0%). The absorption, retention, and balance of zinc were estimated in rats fed experimental and standard ZnSO₄ diets using a balance study. The maximum retention of zinc wasobserved in dehulled soaked, and pressure cooked diets (63.37%) followed by sprouted (48 h) and pressure cooked (61.38%) diets. The gain in body weight, total femur zinc and retention of zinc in liver, kidneys and spleen were found to be highest for rats eating the sprouted pressure cooked diet followed by the dehulled, soaked and pressure cooked diet. Plasma zinc levels were found to range from 3.81 to 6.34 mol/dl; they were maximum for rats fed the dehulled, soaked and pressure cooked diet. It can be concluded that dehulling significantly improves the availability of zinc and germination of ricebeans is the best method to enhance the zinc availability.     

Effects of Varieties and Cooking Methods on Physical and Chemical Characteristics of Cooked Rice

To analyze the effect of different lowland rice varieties and different cooking methods on physical and chemical characteristics of cooked rice. A factorial randomized block design with two factors was used and each combination of the factors was repeated three times. The first factor was rice variety(Ciherang and Ciliwung) and the second factor was the cooking method(stovetop, boiling and steaming, and rice cooker). Results showed that Ciherang and Ciliwung varieties were classified into slender grain rice type with yellowred color. The amylose content of Ciherang was classified as moderate, while the amylose content of Ciliwung classified as low. The most abundant amino acid contained in Ciherang and Ciliwung varieties was glutamic acid. Statistical analysis showed that cooking method had significant effects on texture, lightness, chroma, hue and moisture content of cooked rice. Rice cooked with liwet method had the lowest texture value, lowest lightness value, highest chroma value, and highest moisture content.     

Reversed phase HPLC analysis of α- and β-carotene from selected raw and cooked vegetables

Traditional AOAC colorimetric procedures for carotenoid analysis are known to lack specificity and accuracy. Newer HPLC methods provide the investigator with a more precise tool for carotenoid quantification in foods and tissues. In the present studies, reverse phase HPLC was utilized to evaluate the - and -carotene content in raw and cooked leaves of lettuce, spinach and winged bean as well as in the carrot root. The vegetables were boiled or steamed and the true retention of - and -carotene in the cooked products was determined. Boiling for 30 minutes resulted in a 53 and 40% loss of -carotene from lettuce and carrots, respectively. Full retention or even an increase in -carotene content in boiled winged bean leaves and spinach was noted. Steaming resulted in very good retention of - and - carotene in all vegetables (83–139% retention). Thus, although cooking procedures (especially boiling) may result in oxidative loss of carotenoids in some vegetables, heat treatment increases the chemical extractability of - and -carotene in others. The presence of carotenoproteins in some vegetables may effect the heat stability of extractability of - and - carotene.     

Comparison of the cooking behaviour of the potato cultivars Nicola and Irene with respect to pectin breakdown and the transfer of ions

Summary The potato cultivars Nicola and Irene were investigated with respect to cell sloughing, specific cell surface area, release of pectic material and transfer of ions using a model cooking study. Both cell sloughing and the release of pectic material were higher for the mealy-cooking cultivar Irene. As the respective cell size distributions measured were the same for both cultivars, the difference in release of pectic material could not be explained by a difference in the specific cell surface areas between the cultivars. Additionally, it was recorded that during cooking only 20% of the calcium present in non-cooked tissue was transferred into the cooking medium, whereas more than 70% of potassium and citrate were transferred. The ratios D_a.citr2−/D_a.K+ and D_a.Ca2+/D_a.K+ for water and cooked potato tissue revealed that in water, potassium ions diffused faster than citrate and calcium ions. However, in cooked potato tissue both citrate and calcium ions diffused faster than potassium ions.     

The fate of bioactive compounds during traditional preparation of einkorn wheat (Triticum monococcum L. subsp. monococcum) bulgur

Einkorn wheat bulgur is a traditional food deeply rooted in some areas of Turkey, since ages. The objective of this study was to evaluate the impact of simulated traditional bulgur preparation on einkorn wheat bioactive compound content.A local einkorn wheat grain sample from Turkey was boiled for 2, 3 and 4 h, then dried in a thermo-ventilated oven. Tocols, carotenoids, phytosterols and phenolics, determined as free (FPC) and bound (BPC) phenolic compounds, were analysed in hulled (spikelets) and dehulled (kernels) bulgur samples, to highlight also glumes’ contribute to their content and evolution.Kernel carotenoid and tocol content significantly decreased following bulgur preparation, to an extent of 42–58% and 15–30%, respectively. Phytosterols slightly decreased in cooked (12–19%), with respect to raw kernels. Phenolics showed different patterns, highlighting glumes’ contribute: kernel FPC increased (+87%) after 4 h of boiling, whereas no significant variations were observed for BPC. A drastic decrease of total and BPC (20.5–28.0%), was observed in spikelets following bulgur preparation. Ferulic and p-coumaric acid resulted the most abundant phenolic acids, respectively, in kernels and spikelets.Decreases in tocol, carotenoids and phytosterol contents were observed whereas an increase of kernel FPC content was calculated after cooking.     

马铃薯能生食吗?

马铃薯营养丰富,钾和维生素C含量都很高。很多蔬菜既可以生食也可以煮熟后食用。通常,生食的蔬菜鲜嫩多汁且口感清新。然而有些蔬菜很少用来生食,马铃薯就是其中一种。马铃薯可以生食,但带有一点苦味,因此很少有人生食马铃薯。生的马铃薯其内含有的蛋白酶抑制剂具有潜在的治疗癌症的作用,但生食马铃薯的风险也很大,会导致难消化、产气和腹胀、食源性疾病和中毒等现象。     

Starch gelatinization distribution and peripheral cell disruption in cooking rice grains monitored by microscopy

Starch gelatinization kinetics governs rice cooking behaviour (cooking time and texture). Starch gelatinization however occurs unevenly in the cooking grain. The aim of this study was to investigate the dynamics of starch gelatinization topography in rice kernels cooked in excess water at two temperatures: 75 °C and 95 °C, for times ranging from 5 to 30 min. Gelatinization front position was assessed over time on 40 μm cross sections using four different tracking methods: directly or after iodine staining using a microscope or a stereomicroscope under normal or polarized light. The four methods gave similar results and the obtained kinetics can be used to model starch gelatinization during grain cooking.In parallel, changes in the structure of the peripheral area of cooked grains were investigated on 3 μm cross sections under the same cooking conditions. Microscopic observations by auto fluorescence and after iodine staining revealed dynamic peripheral cell disruption at the same time as starch gelatinization, which may have a major impact on starch leaching and hence on the textural properties of the cooked grain.     

Carotenoid profiling of Hordeum chilense grains: The parental proof for the origin of the high carotenoid content and esterification pattern of tritordeum

The outstanding high carotenoid content of the tritordeum (×Tritordeum Ascherson et Graebner) grains, a promising novel cereal derived from the crossing of durum wheat and the wild barley Hordeum chilense, has previously been assigned as a character derived from the genetic background of its wild parent. The carotenoid profile of H. chilense, especially the lutein esters presented in this study, provide biochemical evidences to confirm this affirmation, being the first time that the individual carotenoid profile of this cereal has been characterized. The total carotenoid content (6.14 ± 0.12 μg/g) and the individual carotenoid composition were very similar to the tritordeum grains, with lutein being the major carotenoid (88%; 5.38 ± 0.11 μg/g) and very low levels of β-carotene. In contrast to tritordeum, H. chilense presented a considerable amount of zeaxanthin (12%; 0.74 ± 0.01 μg/g). Up to 55% of lutein was esterified with palmitic (C16:0) and linoleic (C18:2) acids, presenting a characteristic acylation pattern, in agreement with the tritordeum one, and composed by four monoesters (lutein 3′-O-linoleate, lutein 3-O-linoleate, lutein 3′-O-palmitate and lutein 3-O-palmitate) and four diesters (lutein dilinoleate, lutein 3′-O-linoleate-3-O-palmitate, lutein 3′-O-palmitate-3-O-linoleate, lutein dipalmitate). These data may be useful in the field of carotenoid biofortification of cereals.     

Changes in chemical and selected biochemical components,protein quality,and digestibility of mung bean (Vigna radiata) during gemination and cooking

The effect of germination on the nutritive value of mung beans (Vigna radiata) was studied in raw and cooked samples after 0, 2 and 4 days of germination. Water content increased, but crude protein, lipids, crude fiber, ash and carbohydrates decreased with germination. Trypsin inhibitor activity did not change significantly while hemagglutinins were absent. Essential amino acids (methionine, tyrptophan and lysine) decreased with germination.Net protein ratio (NPR) and protein efficiency ratio (PER) in rats decreased with germination especially in cooked sprouts. True digestibility did not change consistently due to germination or cooking. In conclusion, loss of protein quality in mung beans occurs upon germination and cooking.Publication INCAP/UNU-4.     

Nutrient changes and antinutrient contents of beniseed and beniseed soup during cooking using a Nigerian traditional method

Evaluations of the effect of prolong cooking on the nutrient and antinutrient composition ofbeniseed and beniseed soup were carried out in this study. Proximate, mineral, vitamin A and C and antinutrient compositions of raw beniseed (BS-R), beniseed boiled (BSB) for 15, 30, 45 and 60 min and beniseed soup (BSS) cooked for the same intervals of time were assessed. Results of the proximate composition analyses showed that raw and boiled beniseed had lower moisture content (5.39-5.51%) than beniseed soups (10.06-15.20%). Nitrogen-free extract (total carbohydrates), fats and phosphorus contents were improved in both the boiled beniseed and beniseed soup while calcium and potassium were increased in the boiled seeds and soup samples respectively. Moisture (in the raw and boiled beniseed), ash, magnesium, zinc, iron contents in both the seed and soup were unchanged in all the samples. Vitamins A and C levels of both boiled beniseed and beniseed soup samples were reduced with increase in cooking time. Beniseed soup had higher protein contents than both the raw and boiled beniseed which decreased with increase in cooking time. Beniseed samples provided good sources of energy (572.97-666.05 kcal/100 g). Except for phytate, the levels of antinutrients tested were lower in the raw and boiled beniseed than in the soup samples which decreased with increase in cooking time. The results are discussed with reference to the effect of prolonged cooking on the nutrient requirements of consumers.     

漳州水仙花瓣和副冠类胡萝卜素成分分析及合成途径基因表达研究

采用高效液相色谱（HPLC）分析漳州水仙‘金盏银台’花瓣和副冠中主要类胡萝卜素成分。结果显示,黄色副冠的主要色素成分是叶黄素,含量为3.73×104 μg/g ,β-胡萝卜素的含量很低,仅2.7 μg/g;白色花瓣中各种类胡萝卜素的含量都极低。同时,采用RT-PCR方法分析类胡萝卜素合成途径结构基因PSY、PDS、ZDS、LYCE、LYCB、BCH在‘金盏银台’白色花瓣、黄色副冠,洋水仙‘粉红魅力’白色花瓣、红色花副冠,洋水仙‘嘹亮’黄色花瓣、橙黄色副冠中的表达情况。结果表明,花瓣与同一品种副冠间结构基因     

Effects of wheat cultivar,cooking method,and bulgur type on nutritional quality characteristics of bulgur

The aim of this study was to investigate the effects of different wheat cultivars, cooking methods, and bulgur types on nutritional quality of bulgur. Cultivars, cooking methods, and bulgur types had significant effects on phytic acid, total phosphorus, soluble, insoluble, and total dietary fibre contents of bulgur. Besides, cultivars and cooking methods were found to have significant effects on yellow pigment, thiamine, and riboflavin contents of bulgur. The results indicated that the variation among genotypes was wide on all parameters investigated. Bulgur cooked using the steam cooker cooking method had better nutritional properties. Regardless of the cooking method, fine bulgur type had higher nutritional values. However, it was observed that there were losses in nutritional values (ranging from 17.5% to 55.7%) during bulgur production from wheat. The losses resulted particularly from cooking and debranning steps during bulgur production. It can be concluded that the steam cooker cooking method showed promising results in terms of the nutritional quality of the bulgur.     

The textural analysis of cooked potato. 1. Physical principles of the separate measurement of softness and dryness

Summary The texture of cooked potatoes was described by two physical parameters: softness, resulting from both cell cleavage and cell separation, and dryness, depending on the ratio of cell separation to cell cleavage. The softness of potato tissue was measured by determining its resistance to cutting with a thin stainless steel wire. Softness increased rapidly with cooking time, particularly when the cultivar was predicted tobe soft in texture by published taste panel trials. Raw potato tissue released intercellular fluid from fractured surfaces due to cell cleavage. After cooking less fluid was released, i.e. the texture became drier, as cell separation increased. The erosion of cells from cooked potato tissue by a high-pressure jet of water was used to measure dryness quantitatively. Erosion increased during cooking. Carrot tissue, whose cells do not separate on cooking, did not erode, but anomalous results with apple tissue suggested that measurement of dryness in this way might not be fully independent of softness.