Clifford Hall

Composition and antioxidant activity of raisin extracts obtained from various solvents

Experiments were conducted to determine if the contents of phenolics and browning reaction products and antioxidant activity of raisin extracts were closely dependent on the extraction solvent. Enhanced extraction yields were obtained from solvent containing higher water concentrations. However, total phenolic content (TPC) was highest for extracts obtained from solvent to water ratios of 60:40 (v/v), whereby the extract obtained from ethanol:water (60:40, v/v) had the highest TPC of 375mg gallic acid equivalents (GAE)/100g extract. HMF content was highest in extracts obtained from 60% solvent, regardless of solvent type. The extract obtained from 60% methanol had the highest HMF content at 199μg/g extract. Although the 60% solvents provided extract with high antioxidant components, the antioxidant activity of raisin extracts obtained from 80:20 (v/v) solvent/water was significantly higher than other raisin extracts obtained from different solvent concentrations. Phenolic acids, HMF, and low-molecular-weight flavonoids were responsible for the antioxidant activity, but not the high-molecular-weight flavonoids.

Antifungal Activity Stability of Flaxseed Protein Extract Using Response Surface Methodology

The stability of the antifungal activity of flaxseed (Linum usitatissimum) protein extract was evaluated in this study. Response surface methodology (RSM) using Box-Behnken factorial design was used to evaluate the effects of treatment variables, that is, temperature (50 to 90 degrees C), time (1 to 29 min), and pH (2 to 8), on the residual antifungal activity (RAA) against Penicillium chrysogenum, Fusarium graminearum, Aspergillus flavus, and a Penicillium sp. isolated from moldy noodles. Regression analyses suggested that the linear terms of the temperature and time had significant (P < 0.05) negative effects on the RAA against all test fungi, whereas that of pH had a significant (P < 0.1) positive role on the RAA of all 3 fungi. In addition, the RAA was significantly (P < 0.05) affected by the quadratic terms of time for all fungi, and the quadratic term of temperature played a significant (P < 0.1) role on RAA against F. graminearum. One interaction term (temperature-pH) was found to significantly (P < 0.1) affect the RAA against both Penicillium strains tested. The results indicated that >or= 90% antifungal activity was lost after the protein extracts were heated at 90 degrees C for 8 min except for F. graminearum. At pasteurization condition, >or= 50% activity was retained except for P. chrysogenum. The results also suggested that neutral and alkaline pH favored the antifungal activity stability of the protein extracts. Thus, flaxseed protein might be promising if used as a preservative in foods with neutral or alkaline pH requiring mild heat treatments.

Effects of Boiling, Refrigerating, and Microwave Heating on Cooked Quality and Stability of Lipids in Macaroni Containing Ground Flaxseed

ABSTRACT Research was conducted to determine the effects of boiling, refrigerating, and microwave heating on the cooked quality and stability of lipids in macaroni containing 15% (w/w) ground flaxseed. Boiling increased brightness but decreased redness and yellowness of macaroni containing ground flaxseed. Boiled macaroni and boiled-refrigerated-microwave heated (BRMH) macaroni had similar appearance. After boiling, cooking loss was lower and cooked firmness was greater for macaroni dried at ultra-high temperature (90°C) than at low temperature (40°C). Macaroni fortified with ground flaxseed had lower cooking loss than did nonfortified macaroni. Firmness was greatest with boiled, intermediate with boiled-refrigerated (BR), and least with BRMH macaroni. Cooking in boiling water reduced extractable lipid content of macaroni with flaxseed. Boiled-refrigerated and BRMH macaroni with flaxseed had similar extractable lipid contents and were lower than that for boiled macaroni with flaxseed. Free fatty acid cont...

Acceptability and characterization of extruded pinto, navy and black beans

BACKGROUND Consumption of dry beans has been relatively flat over the last decade. Creating new bean products may increase the consumption of beans and allow more consumers to obtain the health benefits of beans. In this study, pinto, navy and black beans were milled and the resulting flours extruded into puffs. Unflavored extruded puffs were evaluated by untrained panelists using a hedonic scale for appearance, flavor, texture and overall acceptability. The compositions of raw flours and extrudates were characterized. RESULTS Sensory results indicated that all beans met or exceeded the minimum requirement for acceptability. Overall acceptability of navy and pinto beans was not significantly different, while acceptability of black bean puffs was significantly lower. Total protein (198-217 g kg(-1)) in extrudates was significantly different among the three beans. Total starch ranged from 398 to 406 g kg(-1) and was not significantly different. Resistant starch, total extractable lipid and raffinose contents were significantly reduced by extrusion. Extrusion did not affect crude fiber and phytic acid contents. CONCLUSION The minimal effects on protein and fiber contents, the significant reduction in raffinose content and the acceptability of the unflavored extruded puffs support using various bean flours as ingredients in extruded puffed products.

Application of Raisin Extracts as Preservatives in Liquid Bread and Bread Systems

Interest in natural ingredients with multifunctions in food has led to the investigation of the antimicrobial activity of raisins, a traditional baking ingredient. Water and 60% ethanol extracts, and raisin juice concentrate (RJC, a commercial food ingredient) were assessed for their ability to inhibit the growth of ropy-bread-causing Bacillus species. The ability of these additives and raisin paste were tested for antifungal activity in liquid bread model system and bread. In the liquid bread model, concentrations as low as 20 and 36 mg crude extract or RJC per gram media significantly (P < 0.05) reduced the populations of B. licheniformis and B. subtilis, respectively. A significant reduction in the population of Aspergillus flavus and Penicillium chrysogenum was achieved at 80 and 470 mg crude extract per gram media, respectively. Bread formulas containing 7.5% of a water extract (equivalent to 70 mg extract per gram dough) or RJC (70 mg/g dough) produced bread that had equivalent mold-free shelf life. The mean mold-free shelf life of the bread containing 7.5% water extract was 18.1 +/- 3.3 d at room temperature while the negative control was mold free for 9.4 +/- 2.4 d. The antifungal efficacy of the extracts in bread was equivalent to 0.24% calcium propionate in 21 d of storage. Doubling the concentration of the extract did not improve the mold-retarding property in bread. The bread containing raisin paste, the percentage of which in dough was equivalent to 15% raisin extract, exhibited a stronger antifungal activity than did the extracts in bread.

Echinacea as a functional food ingredient.

Publisher Summary This chapter discusses the phytochemical constituents of Echinacea and includes the information relevant to the biological activity, potential safety concerns, detection methods, and the effects of processing on phytochemicals, including potential functional activities (such as antioxidant and antimicrobial activities). Research from the past two decades has shown that Echinacea can enhance the immune system using in vitro and in vivo indicators. In contrast, conflicting results have been reported during clinical evaluations of Echinacea , thus, there is a need to standardize formulas to truly evaluate the effectiveness of Echinacea in biological systems. In addition, further research is needed to establish the safety of Echinacea in light of the reports published on adverse reactions to Echinacea . A variety of studies showing both positive and negative results is presented in the chapter in the hope that a more standard method be adopted for assessing the biological activity of Echinacea .

Composition, Nutritional Value, and Health Benefits of Pulses

The United Nations has declared 2016 as the International Year of Pulses. Pulses are narrowly defined as leguminous crops that are harvested as dry seeds. Although some pulse crops are harvested green (e.g., green peas), these are classified as vegetables because the pods are often consumed along with the mature and sometimes immature seeds. Other dried legumes such as soybean and peanut meet the definition of being a leguminous crop that is harvested as dry seeds; however, these crops are grown primarily for oil content and, thus, are not categorized as pulses. There are hundreds of pulse varieties grown worldwide; these include, for example, dry edible beans, chickpeas, cowpeas, and lentils. This review will cover the proximate (e.g., protein, carbohydrates, vitamins, and minerals), and phytonutrient (e.g., polyphenolics and carotenoid) composition of dry edible beans, peas, lentils, and chickpeas. Soybean and peanuts will not be covered in this review. The effects of processing on composition will also...

Modified Microwave-Assisted Extraction of Ergosterol for Measuring Fungal Biomass in Grain Cultures

Ergosterol is a measure for fungal biomass. The recovery rates using a previously described microwave-assisted-extraction (MAE) method for ergosterol analysis tended to be low for grain cultures (pure culture in sterilized 40% moisture content grain) inoculated with Fusarium graminearum . An improved MAE method for measuring ergosterol in grain cultures was developed and compared. Modification to the original MAE included alterations in duration of microwave exposure and extraction solvents. Four autoclaved grains (wheat, rice, barley, and corn) were inoculated with F. graminearum or spiked with ergosterol at concentrations from 0.88 to 100 microg/g and extracted with both methods. The ergosterol recovery rates were significantly different (p < 0.05) for the two methods in assaying both the spiked and grain culture samples. The modified method provided greater recovery rates than the previously reported MAE method for the spiked samples and F. graminearum grain cultures.

Effects of Extruder Screw Speeds on Physical Properties and In Vitro Starch Hydrolysis of Precooked Pinto, Navy, Red, and Black Bean Extrudates

ABSTRACT Precooked pinto, navy, red, and black bean flours were extruded at different screw speeds (320, 380, and 440 rpm) with a twin-screw extruder. Effect of speed on physical properties and in vitro starch hydrolysis was investigated. Increasing screw speeds reduced water activity, expansion index, and texture. Extrudates could not be obtained from pinto bean flour at 440 rpm because of the high shear effect. Water absorption index and water solubility index were not significantly affected by screw speed but were significantly higher than for unextruded precooked flour. A significant change in color was observed in navy beans, characterized by increasing b values on the Hunter color scale. Resistant starch ranged from 3.65 to 4.83% db and was not significantly affected by screw speed. Glycemic index of all extrudates was high, ranging from 81.3 to 86.9.

Physicochemical Properties of Flaxseed Fortified Extruded Bean Snack

Milled flaxseed was incorporated (0–20%) into a combination of bean-corn flours and extruded in a twin screw extruder using corn curl method. Physicochemical parameters such as water activity, color, expansion ratio, bulk density, lipid content, and peroxide values of extruded snack were analyzed. Scanning electron micrographs were taken. Peroxide values and propanal contents were measured over four months of storage. Rancidity scores of extruded snack were measured using a trained panel. As expected, omega-3 fatty acids and bulk density increased with increasing flaxseed fortification levels. Extrudates with more flaxseed had decreased lightness values and expansion ratios. However, only the 15 and 20% flaxseed containing extrudates had expansion ratios that were significantly (P ≤ 0.05) different from the control. In general, no significant difference (P > 0.05) in water activity values was observed in the flaxseed fortified extrudates, except in the navy-corn based extrudates. Peroxide values increased with increased flaxseed levels and over a storage period. However, propanal values did not change significantly in the 5–10% flaxseed fortified extrudates but increased in extrudates with higher levels of flaxseed. Rancidity scores were correlated with peroxide values and did not increase significantly during storage under nitrogen flushed conditions.