Water Holding Capacity of Hemicelluloses from Fruits, Vegetables and Wheat Bran

The water-holding capacities of freeze-dried bean, cabbage, lettuce, onion, peach, pear, pumpkin, tomato, wheat bran and their hemicelluloses were determined by the centrifugation method. Cabbage had the greatest water-holding capacity at 35.8g of water per gram of dry food; bran the lowest at 5.2g water per gram. The waterholding capacity (WHC) of the hemicelluloses from fruits and vegetables varied considerably from 3.3 g/g in beans to 12.0 g/g from cabbage. Hemicelluloses extracted from wheat bran showed a marked increase in WHC from 5.2 g/g of water per gram of‘whole’bran to 22.8 g/g for hemicellulose. This decreased to 15.3g of water bound by hemicellulose that had been extracted after chlorite delignification. WHC of hemicelluloses from wheat bran and cabbage may account for their ability to increase stool weight.     

Folate content in foods commonly consumed in Egypt

The folate content in some Egyptian foods was determined using RP-HPLC-FL. Trienzyme treatment was used for legumes, dienzyme treatment for cereals and starchy vegetables, and monoenzyme treatment for vegetables and fruits. The highest folate content (633 μg/100 g) was found in dried Jew’s mellow due to low water content, followed by legumes (e.g. 150 μg/100 g for chick peas) and leafy vegetables (100 μg/100 g). For other foods, folate content ranged from 10–90 μg/100 g. In all foods, the predominant folate form was 5-CH₃–H₄folate, except for dried Jew’s mellow, which contained more than 80% 10-HCO–PteGlu. Using folate data from our own analyses and food tables and food consumption data, the dietary folate intake per capita in Egypt was estimated. However, representative and validated food composition data for folate in Egyptian foods are needed for estimating and evaluating the adequacy of the population’s folate intake.     

Effects of Processing on the Compositions and Physicochemical Properties of Fibre Concentrate from Cooked Fruit Pomaces

This study examined the influence of applied technologies namely desugaring, grinding, and bleaching on the compositions (cellulose, hemicelluloses, lignins, and pectins), physicochemical properties (water-holding capacity (WHC), swelling capacity (SWC), oil-holding capacity (OHC)) and the colour of dietary fibre (DF) during the production of fibre concentrates from unusual cooked apple and pear pomaces. Thermogravimetric analysis (TGA) and optical microscopy were also performed to monitor process-induced modification. All the processing conditions affected the compositions and physicochemical properties of DF. The bleaching treatment induced the greatest changes on DF producing yellow cellulose-rich fibre concentrates with improved WHC from 3.2 to 10.0 g/g and improved SWC from 4.0 to 8.8 ml/g. Otherwise, reduction of the particle size influenced hydration properties and colours of DF. WHC and SWC tended to increase with the particle size whereas smaller granulometric size increased the lightness of fibres. Desugaring increased the DF content in both pomaces by 1.2-fold with slight modification of apple insoluble dietary fibre ratio. Fibre concentrates had improved WHC and SWC up to 1.4-fold. All processes had no significant effect (p?<?0.05) on OHC of DF except with ultrafine apple fibre concentrates. Results showed that processing had overall positive effects on DF contents and hydration properties of pomaces from cooked fruits. Bleached fibre concentrates from apple pomace had the highest WHC (10.0 g/g) whereas that of pear had the highest fibre content (89.9 %). Fibres from cooked fruit pomaces may therefore be used as textural ingredients or functional foods.     

Zinc levels in foods from southeastern Spain: relationship to daily dietary intake.

The zinc content of 300 food and 79 beverage samples was determined using flame atomic absorption spectrometry. Sample recoveries, repeatability, and analyses of NIST and CBR-CEC reference materials demonstrated the reliability and accuracy of this technique. Mean zinc concentrations varied from 0.02 microg/ml in fresh water to 71.0 microg/g (fresh weight) in pork liver. The daily dietary intake of zinc for inhabitants of southeastern Spain was estimated to be 10.1 mg (5.5, 4.0, 0.5, and 0.1 mg Zn/day per person from foods of animal and vegetable origin, drinks, and other foods, respectively). Zinc levels found in high protein foods (meat, fish, milk products, eggs, dry fruits, cereals and legumes) were significantly higher than those found in food with a low protein content (vegetables, fruits and drinks) (p < 0.001). A significant linear correlation between zinc levels and the corresponding protein content of cereals, legumes and dry fruits was found (r = 0.754, p < 0.005). Zinc concentrations in milk samples were significantly modified by the thermal treatment (p < 0.001), and the skimming (p < 0.05) and calcium enrichment processes (p < 0.001). Shellfish zinc levels were also significantly higher than those measured in fish (p < 0.05). Mean zinc concentrations found in cheese were statistically higher than those determined in the remaining milk products (p < 0.001). Zinc levels measured in distilled beverages were also statistically lower than those found in fermented ones (p < 0.001).     

Antioxidant and micronutrient quality of fruit and root vegetables from the Indian subcontinent and their comparative performance with green leafy vegetables and fruits

Commonly consumed, fruit vegetables (12) and root vegetables (15) in the Indian subcontinent in cooked and uncooked states assessed for inhibition of thiobarbituric acid reactive substances (TBARS), superoxide radical scavenging activity (SOSA), ferrous iron chelating ability (FICA) and nine micronutrients, exhibited large variability in these parameters. SOSA and FICA were significantly associated (r = 0.803, p < 0.001) with each other. Inhibition of TBARS showed marginal correlation with both FICA (0.38, p < 0.05) and SOSA (0.29, p > 0.05). There were significant cooking losses for each of the assessed antioxidant capacity parameters (p < 0.05). Contents of ascorbic acid, per 100 g of cooked fruit and root vegetables were high (61.9 and 31.3% of recommended daily allowance (RDA)). However, both the food classes were not good sources of beta‐carotene, riboflavin and thiamine (1.66–5.26% RDA). When compared with our data on 30 cooked green leafy vegetables (GLV) and 30 fresh fruits, root vegetables showed significantly (p < 0.05) higher levels of zinc and selenium. Cooked root vegetables were comparable with cooked GLVs but uncooked GLVs gave the highest values for inhibition of TBARS (0.73 ± 0.21 mM vitamin E/100g). SOSA (40.7 ± 15.6 mM tannic acid/100g) and FICA (41.6 ± 14.9 mM EDTA/100g) were highest for uncooked fruit vegetables. Root vegetables had the highest levels of polyphenols (251.4 ± 107.3 mg/100g). For the present study, popular fruits and vegetables such as guava, spinach, bitter gourd (Momordica charantia), yam, ginger and beetroot, and also less common ones like bael (Aegle marmelos), kokum (Garcinia indica) and mango‐ginger (Curcuma ameda), showed potential in vitro to combat oxidative stress. Copyright © 2005 Society of Chemical Industry     

雪莲果体外抗氧化和自由基清除能力

抗氧化能力是衡量果蔬营养及保健价值的重要指标之一。雪莲果是一种药食两用植物,对多种慢性疾病有缓解作用。分别采用5 种方法(DPPH、ABTS、FRAP、SASR 和MCC)对雪莲果块根甲醇提取液的自由基清除能力及抗氧化活性进行体外评价。结果表明：DPPH 法测定的Trolox 当量抗氧化能力(TEAC)为410.263mg Trolox/g md,抗坏血酸当量抗氧化能力(AEAC)为230.485mg VC/g md,IC50 值为1.464mg/mL;ABTS 法测定的TEAC 为267.584mg Trolox/g md,AEAC为41.597mg VC/g md,IC50 值为1.269mg/mL;SRSA 法测定的TEAC 为652.816mg Trolox/g md,AEAC 为101.451mg VC/g md,IC50 值为7.720mg/mL。说明雪莲果块根提取物对DPPH 自由基、ABTS+·和O2·三种不同的自由基均有一定的清除活性。此外,雪莲果块根提取物还具有较高的总抗氧化(FRAP 值为131.723 mgFeSO4/g md)和较强的金属螯合能力(73.193%)。     

KINETIC MODELING OF VEGETABLE COOKING AT 100C

Kinetics of cooking of green peas, carrot, radish and knolkol were determined from the compression force ratio of the vegetables before and after cooking. The kinetics of rice and potato cooking, both starchy products were found to be suitable in explaining the kinetics of cooking of vegetables. The degree of cooking was correlated to cooking time and the reaction rate constant, K, value was determined for four vegetables. With this K value the degree of cooking at various other cooking times was predicted. The R² value and standard error of estimate were determined.     

Copper and zinc contents of Nigerian foods and estimates of the adult dietary intakes

Concentrations of copper and zinc were determined in 80 Nigerian food items of various classes which were obtained from the markets of Ibadan city. These consisted of leafy and fruity vegetables, tubers, fruits, meats, fish, legumes, cereals, spices, dairy products, sweeteners, fats and oils, confectioneries, canned foods and alcoholic beverages. Copper levels ranged widely from 0.06 to 13.3 mg/kg, while zinc levels ranged from 0.06 to 56.9 mg/kg in various foods. The differences in mean metal levels were found to be significant (P=0.05) among the various food classes. Highest levels of both metals were found to occur in legumes (Cu, 8.3±3.7 mg/kg; Zn, 29±12 mg/kg). The levels of the metals compare well with those which have been obtained in foods from studies elsewhere in the world. The dietary intakes of both metals for the adult population was found to vary with the income groups, with higher intakes being estimated for higher income groups. The estimated weighted average dietary intakes for the entire adult population were calculated to be 2.64 mg Cu/day and 15.8 mg Zn/day.     

卡拉胶、转谷氨酰胺酶及大豆分离蛋白对猪PSE肉低温香肠保水性和感官品质的影响

为研究卡拉胶、转谷氨酰胺酶（transglutaminase,TG）及大豆分离蛋白对猪PSE（pale、soft、exudative）肉低温香肠保水性和感官品质的影响,通过单因素试验和L9（34）正交试验,以蒸煮损失和感官品质为参考指标,确定最适添加量。结果表明：单独添加卡拉胶或大豆分离蛋白可以明显改善猪PSE肉低温香肠的蒸煮损失（P＜0.05）,TG添加量超过0.6%会导致猪PSE肉低温香肠的保水性发生显著下降（P＜0.05）;正交试验进一步优化后确定卡拉胶、TG及大豆分离蛋白的最适添加量分别为0.5%、0.2%和4%;通过优选后的正交工艺进行验证发现,该工艺对猪PSE肉低温香肠的保水性和感官品质有明显的改善作用。     

Fermentation by Amylolytic Lactic Acid Bacteria and Consequences for Starch Digestibility of Plantain, Breadfruit, and Sweet Potato Flours

The potential of tropical starchy plants such as plantain (Musa paradisiaca), breadfruit (Artocarpus communis), and sweet potato (Ipomoea batatas) for the development of new fermented foods was investigated by exploiting the capacity of some lactic acid bacteria to hydrolyze starch. The amylolytic lactic acid bacteria (ALAB) Lactobacillus plantarum A6 and Lactobacillus fermentum Ogi E1 were able to change the consistency of thick sticky gelatinized slurries of these starchy fruits and tubers into semiliquid to liquid products. Consequently, a decrease in apparent viscosity and an increase in Bostwick flow were observed. These changes and the production of maltooligosaccharides confirmed starch hydrolysis. Sucrose in sweet potato was not fermented by strain A6 and poorly fermented by strain Ogi E1, suggesting possible inhibition of sucrose fermentation. In all 3 starchy plants, rapidly digestible starch (RDS) was higher than slowly digestible starch (SDS) and resistant starch (RS) represented between 17% and 30% dry matter (DM). The digestibility of plantain was not affected by fermentation, whereas the RDS content of breadfruit and sweet potato decreased and the RS content increased after fermentation. Practical Application: The characteristics resulting from different combinations of gluten free starchy plants (plantain, breadfruit, sweet potato) and amylolytic lactic acid bacteria (ALAB) offer opportunities to develop new functional fermented beverages, mainly for breadfruit and sweet potato, after further investigation of their formulation, sensory attributes, nutritional, and prebiotic characteristics.     

Mineral content of tropical fruits and unconventional foods of the Andes and the rain forest of Colombia

A total of 68 species of starchy foods, tropical fruits, leaves and tubers (101 samples), were collected on the foothills of the Colombian Andes and in the rain forests of the Colombian Pacific coast. Their edible portion was analyzed for mineral content (Ca, P, Mg, K, Na, Cl, S, Mn, Zn, Fe, Cu, Se, Co, Ni). The foods were generally high in K (36–1.782 mg K/100 g edible portion) and low in sodium (<45 mg Na/100 g edible portion). The tree foliages had the highest contents in most of the elements, especially in calcium (280–1242 mg Ca/100 g edible portion, i.e., up to 62 g Ca/kg dry matter) and iron (0.7–8.4 mg Fe/100 g edible portion). Correlations (P < 0.001) were observed between total ash and many elements, especially Ca and Mg (r =  0.77 and 0.73, respectively). High correlations were also obtained between Ca and Mg (r = 0.93).     

Food patterns during an economic crisis among pregnant women in Purworejo District, Central Java, Indonesia

A cross-sectional study was conducted between 1996 and 1998. Six 24-hour recalls were performed during the second trimester of pregnancy among 450 women in Purworejo District, Central Java, Indonesia. The objectives of the study were to assess the food intake and food pattern among pregnant women before and during the economic crisis. Before the crisis, rich women had the highest intakes of animal foods, fats and oils, and sugar. Food intake among the urban poor and the rural landless poor subgroups was influenced by the emerging economic crisis. Although the price of rice increased, the intake of rice also increased among all subgroups. Rural poor women with access to rice fields increased their intake of rice and decreased their intake of nonrice staple foods (p < .05). There were significant decreases in the consumption of chicken by rich women and rural poor women with access to rice fields (p < .05). Rice was a strongly inferior good and remained an important supplier of energy, protein, and carbohydrate. Nuts and pulses were important suppliers of calcium and iron, and vegetables were an important supplier of vitamin A. Rich women increased their intake of nuts and pulses, vegetables, fats and oils, and sugar when their intake of rice increased (p < .05). The food patterns were based on rice, nuts and pulses, and vegetables, i.e., plant food. All but the rich women decreased their intake of nutritious foods such as meat, chicken, and fruits. The intake of nuts and pulses and of vegetables increased, whereas the intake of cooking oil and sugar remained constant.     

Effects of Phosphates and Salt in Ground Raw and Cooked Farmed Cod (Gadus morhua) Muscle Studied by the Water Holding Capacity (WHC), and Supported by 31P-NMR Measurements

ABSTRACT:  A model system consisting of ground farmed cod muscle (80%, w/w) and added brine (20%, w/w) with different content and combinations of salt (0% and 3% in brine) and phosphorus compounds (mono-, di-, tri- and hexametaphosphates; 0% and 3% in brine) was used to simulate industrial brining of muscle foods. Individual phosphorus component concentrations and breakdown as function of time (0, 23 h) were analyzed using ³¹P-NMR spectroscopy. The effects of salt and phosphate on water holding capacity (WHC) were measured at similar sampling times, and interrelations between phosphorous components determined by NMR and WHC were established. Addition of salt led to a significant increase (+18%) in WHC, and the combined effect of salt and phosphates was even more pronounced (+29%). The positive effect of triphosphate and salt on WHC was also seen after cooking (+36% in raw and +41% in cooked cod muscle, relative to control), although NMR analysis showed a rapid breakdown of di- and triphosphates.     

A COMPARISON OF MICROBIOLOGICAL AND RADIOIMMUNOASSAY METHODS FOR THE DETERMINATION OF PANTOTHENIC ACID IN FOODS

Seventy-five foods were analyzed for the vitamin pantothenic acid using a microbiological assay and a new radioimmunoassay (RIA). The food sample extract used in both assays was the result of dialysis after enzyme hydrolysis. In the method used previously, the food-enzyme mixture had been filtered.
A very high correlation (r²=.94) between the results from the RIA and the microbiological assay was found. There was a statistically significant difference between the two assay results for all foods and for the subgroups meats, breads and cereals, and fruits and vegetables at p=.05. At p = .01 breads and cereals and fruits and vegetables did not have significantly different results between the two assay methods. For all foods and all subgroups, the microbiological assay produced a higher mean result than the RIA.
The RIA is an acceptable method for assaying pantothenic acid in breads and cereals and fruits and vegetables. Futher study is needed to determine how components of meat interact with one or both assay systems.     

微波加热及NaCl添加量对牦牛肉糜凝胶特性和保水性的影响

微波加热是食品加工的一种新型技术,为探讨微波加热对牦肉糜凝胶特性的影响,采用单因素试验设计,研究微波加热的时间、功率以及NaCl添加量对牦牛肉糜凝胶质构特性和保水率的影响。以水浴为对照组,利用质构仪测定牦牛肉糜凝胶硬度、咀嚼性、弹性和回复性。结果表明：随着对牦牛肉糜微波加热时间的延长,其凝胶硬度、咀嚼性、弹性逐渐下降（P＜0.05）,回复性逐渐增加（P＜0.05）,保水率显著下降（P＜0.05）;而随着微波功率增大,牦牛肉糜凝胶的硬度、咀嚼性降低（P＜0.05）,弹性变化不大（P＞0.05）,蒸煮损失率明显增加（P＜0.05）;同时,随着NaCl添加量增加,牦牛肉糜凝胶保水率显著增加（P＜0.05）。本研究为微波技术在肉制品加工中应用提供了理论依据。     

谷氨酰胺转氨酶对鸭胸肉糜凝胶性能的影响

以鸭胸肉糜为研究对象,探讨不同谷氨酰胺转氨酶（transglutaminase,TG）添加量（0（T1）、2（T2）、4（T3）、6（T4）、8 g（T5））对肉糜保水性、色差、质构和水分分布状态的影响。结果表明：添加TG酶显著提高鸭胸肉糜的亮度值（L*）、蒸煮得率和质构参数（P＜0.05）,降低红度值（a*）和黄度值（b*）;鸭胸肉糜的L*、蒸煮得率和质构特性随着TG酶添加量的增加而显著提高（P＜0.05）,但T4和T5组差异不显著（P＞0.05）;鸭胸肉糜的T21和T22起始弛豫时间随着TG酶添加量的增加显著缩短（P＜0.05）,T21的峰面积比例显著增加,T22的峰面积比例显著降低（P＜0.05）,表明水分的流动性降低,但T4和T5组差异不显著（P＞0.05）。综上所述,711.6 g鸭胸肉糜中添加6 g TG酶时保水性和质构最佳。     

Comparison of 3 Spectrophotometric Methods for Carotenoid Determination in Frequently Consumed Fruits and Vegetables

ABSTRACT: Carotenoids are C-40 tetraterpenoid compounds with potential health beneficial effects. Major dietary sources include a variety of fruits and vegetables. Rapid screening methods are therefore desired, but their accuracy varies depending on the carotenoid profile and the matrix of the plant food. In the present study, 3 different methods were compared, all based on a rapid extraction protocol and spectrophotometric measurements to determine the total amount carotenoids present in fruits and vegetables (n = 28), either with or without chlorophyll. Published methods (a) Lichtenthaler and (b) Hornero-Méndez and Mínguez-Mosquera were compared with a newly developed method (method c) based on the average molar absorption coefficient (135310 Lcm⁻¹mol⁻¹) and wavelength (450 nm in acetone), for the 5 predominant carotenoid species (beta-carotene, zeaxanthin, lycopene, lutein, beta-cryptoxanthin) in the investigated foods. All results were compared to HPLC (method d). To avoid overestimating carotenoid concentrations due to chlorophyll A and B presence, the effect of saponification was studied for all methods. Overall, saponification led to significant carotenoid losses (12.6 ± 0.9%). Methods a, b, c, and d yielded 5.1 ± 0.4 mg/100 g, 4.6 ± 0.5 mg/100 g, 4.3 ± 0.5 mg/100 g, and 4.2 ± 0.5 mg/100 g total carotenoids, respectively, with method a leading to significant higher mean concentrations compared to all other methods (P < 0.001, Bonferroni) with methods b and c being not significantly different and highly correlated compared to HPLC (> r = 0.95). Similar results were found when stratifying for chlorophyll content and fruits compared with vegetables, however, accuracy varied for individual fruits, highlighting the limitation to use the same method for all plant foods. Practical Application: This study presents a comparison of various rapid spectrophotometric measurements to determine total carotenoid content in various fruits and vegetables and could aid in the selection of the appropriate method for individual plant foods with different carotenoid profile and matrices.     

Effect of starch type and its modifications on physicochemical properties of bologna-type sausage produced with sheep tail fat

Gelatinized, solubilized/dispersed and retrograded starches were produced from normal (unmodified) corn and potato starches, and were used with sheep tail fat for sausage batters. Emulsion stability, jelly and fat separation, water holding capacity (WHC), emulsion viscosity and batter pH were determined. Penetrometer reading after cooking of the batters, and tenderness of the end-product were determined. Modified starches statistically (p<0.01) affected emulsion stability and emulsion viscosity. The modification process was not significant for pH, WHC, jelly and fat separation and penetrometer values (p>0.05). While type of used starch had a significant effect on jelly and fat separation (p<0.05), for the other measurements it was not significant (p>0.05).     

Antioxidant Potential and Polyphenol Content of Selected Food

Phenolic compounds are natural antioxidants present in plant foods, which are important to human health. This study aimed to measure the total antioxidant potential with the FRAP (Ferric Reducing Antioxidant Power) method and the total polyphenol content of 44 common consumed foods; represented by vegetables, pulses, fruits, cereals and breads. The antioxidant potential ranged: in vegetables 0.033–3.209, in pulses 0.342–0.387, in fruits 0.312–2.833, and in cereals and breads 0.062–1.709 mmol/100 g in fresh mass, respectively. The antioxidant potential of the foods tested was related to the total polyphenol contents.     

Model analysis of sorption isotherms

The equation developed by Blahovec and Yanniotis, which is based on surface adsorption and solution water, was applied for fitting experimental sorption data for starchy and high protein foods, fruits and vegetables, nuts, legumes, and seeds. Analysis of sorption isotherms shows that surface adsorption is more important than solution water in the isotherms for cereals, potatoes, legumes and seeds, while in vegetables, fruits, meat, milk products and some nuts solution water is more important. The ratio of solution water to surface adsorption increases as water activity increases, it is higher for the adsorption isotherm than the desorption isotherm at any water activity value and decreases as temperature increases.