Optimisation for resveratrol accumulation during peanut germination with phenylalanine feeding & ultrasound‐treatment using response surface methodology

Germinated peanut has been used as a novel functional food these days, which has almost six times trans‐resveratrol to peanut seeds. Resveratrol is a natural occurring stilbene phytoalexin phenolic compound produced in response to a variety of biotic and abiotic stresses. In this study, we investigated the effects of ultrasonic treatments and phenylalanine feeding simultaneously on enhancing resveratrol during peanut germination. The influences of germinal time, phenylalanine concentration as well as ultrasound frequency, treatment temperature and time on resveratrol accumulation in germinated peanut were studied, respectively. Subsequently, based on Box–Behnken design, interactive effects of the phenylalanine feeding & ultrasound parameters were evaluated. The optimum conditions for resveratrol accumulation were as follows: phenylalanine concentration at 0.8 mm , ultrasonic power at 240 W, ultrasonic treatment time at 30 min and ultrasonic treatment temperature at 35 °C. Using the optimum condition, resveratrol concentration in germinated peanuts reached 36.99 μg g^?1 (DW), which was almost 9.4 times higher than that in the nongerminating peanut.     

Effects of soaking and aeration treatment on γ-aminobutyric acid accumulation in germinated soybean (<Emphasis Type="Italic">Glycine max</Emphasis> L.)

Effects of soaking temperature, soaking time, opportunity of aeration treatment, culture temperature, pH value, and air flow rate on γ-aminobutyric acid (GABA) accumulation during germination of soybean (Glycine max (L.) Merr.) were investigated in this study. The objective of this study was to optimize the culture conditions of GABA production in germinated soybeans. Results showed that soaking at 30 °C for 4 h was found to be the most effective soaking ways that made soybean seeds have sufficient moisture, satisfactory germination, and GABA accumulation. The suitable stress opportunity was dark culture for 2 days with distilled water and then hypoxia stress in aerated culture medium for 2 days in a dark incubator at 30 °C. Under these conditions, the maximum GABA content (2.24 mg/g DW) was 3.5 times higher than the initial sample of aeration treatment (0 h) and 12.5 times higher than the raw material. Correlation analysis also revealed that GABA accumulation was significantly correlated to the corresponding physiochemical indexes (p < 0.01). Box-Behnken experimental analysis showed that the optimal condition with aeration treatment for GABA accumulation in germinated soybean was at a temperature of 30.5 °C, a pH value of 4.1, and an air flow rate of 0.9 L/min; the predicted highest GABA yield was 2.60 mg/g DW, which was 15.2 times higher than raw seeds. Analysis of variance and confirmatory trials for the regression model suggested that the model can quite exactly predict GABA accumulation in soybean during germination.     

Effects of roasting on phenolics composition and antioxidant activity of peanut (<Emphasis Type="Italic">Arachis hypogaea</Emphasis> L.) kernel flour

The effects of roasting on the phenolics composition and antioxidant activity of peanut (Arachis hypogaea L.) kernel flour were appraised. Peanut kernel flour, with and without skin, were roasted at 160 °C for 10, 20, 30, 40 and 50 min. The resultant changes in the antioxidant activity of roasted peanut kernel flour were assessed by the determinations of total phenolics, 1,1-diphenyl-2-picrylhydrazyl free radical-scavenging capacity, percent inhibition of linoleic acid oxidation and thiobarbituric acid test and compared with those of unroasted kernel flour. It was observed that roasting significantly (p < 0.05) increased the antioxidant activity of the peanut kernel flour. HPLC analysis revealed the detection of three phenolic acids (p-hydroxybenzoic, chlorogenic, p-coumaric), two flavonols (quercetin, kaempferol), and a stilbene (resveratrol) both in the roasted and unroasted samples. In peanut kernel flour without skin, the contents of the phenolics increased in the initial roasting phase, however, decreased gradually in the later phase (>20 min of roasting time). In contrast, over the course of heating, the amounts of phenolics were noted to be slightly increased in the peanut kernel flour with skin; the most significant (p < 0.05) increase occurred in the concentration of p-coumaric acid and quercetin at 30, 40, and 50 min of roasting. The results of this study reveal that optimum roasting time should be sought to enhancing the antioxidant capacity and phenolics concentration in peanut kernel flour.     

Effect of selenium fortification during sprouting of peanut seeds receiving HVEF and selenium soaking combination on yield,selenium and resveratrol contents,anti-oxidative properties,and microbial control

Selenium (Se) is essential for human nutrition as it involves many biological functions. In this study, three seed treatments (water soaking, high-voltage electric field (HVEF), HVEF and water soaking), and two Se fortification treatments (Se soaking with Se fortification during sprouting and HVEF plus Se soaking with Se fortification during sprouting) were used to examine their effects on peanut seed germination, Se contents and microbial loads on 8-days-old peanut sprouts. The results indicated that the best treatment for enhancing germination (99.6%), increasing the sprout's total Se and resveratrol contents (61.32 and 46.32 μg g ⁻¹ , respectively) was HVEF plus Se soaking in combination with Se fortification. It also reduced the microbial loads to <3 log CFU g⁻¹ FW on the resultant 8-days-old peanut sprouts. Thus, the treatment of HVEF and Se soaking combination with Se fortification can be used to produce Se-fortified peanut sprouts with improved nutritional quality and microbial control.     

花生发芽过程中基础成分变化及白藜芦醇的诱导富集

以8种花生种子为原料,探究发芽4 d过程中各品种花生发芽率、芽长、基础成分和白藜芦醇含量的变化,并优选出3个品种(花育22、花育25和花育50),分别采用低温、超声、紫外、添加诱导剂苯丙氨酸和水杨酸对白藜芦醇进行富集。结果表明,发芽过程中,各品种发芽率和芽长呈现不同程度的增长,营养成分也发生改变,水分、游离氨基酸均显著增加,粗脂肪、可溶性蛋白总体均显著下降,灰分、粗蛋白和总糖的含量总体上不发生变化,活性成分白藜芦醇的含量也显著增加,最高达144.72 μg/100 g。此外,进一步通过对比3个品种发芽2 d时各诱导处理组与对照组白藜芦醇的含量可知,超声、紫外以及添加苯丙氨酸的处理对发芽过程中白藜芦醇均有显著的富集作用。     

Improvement in sprouted wheat flour functionality: effect of time,temperature and elicitation

This study was aimed at optimising conditions of wheat germination (temperature, time of sprouting and elicitation) to improve its phenolics content, antioxidative capacity and nutritional quality. Total phenolics and antioxidant potential were improved most effectively after 4 days of sprouting at 20 °C. The highest reducing ability and the ability to quench free radicals (1.24 mg Trolox equivalent (TE) g^?1 d.m. and 0.38 mg TE g ^?1 d.m., respectively) were determined for 4‐day‐old control and willow + yeast elicited sprouts germinated at 20 °C. The kinetics of starch and protein mobilisation were affected by sprouting conditions. The highest protein digestibility was found for 2‐day‐old sprouts germinated at 20 °C, whereas the lowest for 4‐day‐old sprouts germinated at 25 °C. Starch was more effectively mobilised during germination at 25 °C. Sprouting conditions were found to effectively modify the quality of sprouts. A key role was ascribed to time and temperature of sprouting, whereas the effect of elicitation was marginal.     

Effects of storage period and temperature on the technological properties,starch digestibility,and phenolic compounds of mung beans (Vigna radiata L.)

This study aimed to evaluate the effects of storage period (0, 2, 4, and 6 months) and temperature (15 °C, 25 °C, and 35 °C) on the germination, vigor, technological properties, starch digestion, and phenolic compound content of mung beans. The germination, vigor, protein solubility, inhibition of the ABTS radicals, and the total free and bound phenolic compound content reduced while cooking time, leached solids, and electrical conductivity increased during storage. Minor changes were observed in grains stored at 15 °C. Starch digestion was higher in stored grains than in freshly harvested beans; however, it decreased on increasing the temperature. The content of bound gallic acid, bound chlorogenic acid, free and bound ferulic acid, free and bound rutin, and free and bound quercetin contents reduced after storage. In contrast, the content of bound caffeic acid, bound vanillic acid, bound myricetin, free coumaric acid, and free catechin contents increased after storage at 15 °C. These results suggested that mung beans could be cooled at 15 °C to reduce the detrimental effects of storage and maintain the nutritional value and germination viability.     

Optimization of Soaking Duration and Temperature for Two Nigerian Rice Cultivars

Optimization of soaking duration and temperature for two Nigerian rice cultivars were evaluated. Temperatures of 50°C, 70°C and 90°C were used for both long and short grain rice paddy. Each treatment had three replicates of 12, 18 and 24 h of soaking durations. The physical analysis of the long/short rice paddies were 1000 kernel volume 24.3/22.3 cm³, 1000 kernel weight 24.2/24.3 g, density 1.3/1.1 gcm³, length, 9.9/8.2 mm, width, 2.95/3.3 mm, water absorption rate of 34/11% and moisture content of 14/11% respectively. Sensory evaluation of the long/short grain rice yield based on colour and general acceptability showed that significant differences existed among the samples with colour 8.05/7.85, general acceptability 8.10/7.80 respectively. The long/short grain percentage breakages were 2.7/1.2% and total yield 70/67%, respectively. At 70°C long grain rice yield increased as soaking duration increased, and at 90°C, short grain rice yield increased as soaking duration increased. The best quality was achieved by soaking the long grain at 70°C for 24 h and short grain at 90°C for 24 h.     

Production of Peanut Flour from Microwave Vacuum-Dried Peanuts

Defatted peanut flours with significantly reduced raw peanut taste and nitrogen solubility of 85+% were produced from field Runner peanuts that had been microwave-vacuum-dried to maximum temperatures of 80°C and 96°C. The flours were prepared from 4.54 kg of peanuts, dried from 25.5% to less than 10% moisture, at 375 Torr absolute pressure and at 1400 and 813 watts microwave power (2450 MHZ). Peanut temperature at end of drying significantly affected the intensity of the raw peanut flavor. Storage at 23.9°C for 14 months had no significant effects on intensity of the raw peanut flavor. Hexane extraction of blanched peanut kernels showed that mass velocity percolation rates increased with increase in final drying temperature of peanuts.     

Effect of time and temperature on bioactive compounds in germinated Brazilian soybean cultivar BRS 258

The objective was to determine the effect of time and temperature on the concentration of bioactive compounds during germination of Brazilian soybean cultivar BRS 258. The concentration of bioactive compounds was optimized using Response Surface Methodology, with a 2² central composite rotational design and germination time and temperature as independent variables. Germination was carried out in a germination chamber, using paper in trays containing 500 g of seeds. Germination temperature and time modified the concentrations of bioactive compounds within the ranges studied. An increase in germination time at 25 °C decreased the concentration of Bowman–Birk inhibitor, lectin and lipoxygenase. After 63 h of germination, a temperature increase from 20 °C to 30 °C resulted in a decrease of lipoxygenase activity by 22.5%. Optimal increases in the concentrations of isoflavone aglycones (daidzein and genistein) and saponin glycosides were observed with a 63 h germination time at 30 °C. Both germination time and temperature had an influence on the composition and concentration of bioactive compounds in germinated soybean flour. Equations determined can be used to predict concentrations of bioactive compounds in germinated soybeans in relation to climate changes and thus optimize their potential use in human health and nutrition.     

Beneficial Influence of Short‐Term Germination on Decreasing Allergenicity of Peanut Proteins

Most allergenic storage proteins in peanuts are degraded during seed germination. By altering this natural physiological process, it might be possible to reduce peanut protein allergenicity. However, little is known about the change in allergenic proteins and their corresponding immunocreactivity, and the effects of major environmental conditions on their allergenicity during germination. In this study, the influence of different germination conditions (temperature and light) on the degradation of Ara h1 and allergenicity changes of peanut seeds was evaluated by ELISA and Western blotting. The results showed that the 40‐ and 65‐kDa proteins in peanut seeds degraded rapidly during the time course, beginning at 60 (at 25 °C) and 108 h (at 20 °C), and the corresponding immunocreactivity of Ara h1 decreased approximately one‐third after 5 to 7 d of germination. Compared with the cotyledons, the embryonic axes had a higher proportion of Ara h1, which was then degraded relatively faster during germination, resulting in a significant reduction in its allergenicity. Although a higher temperature improved the seed germination rate, it affected sprout quality (as did light); therefore, 25 °C and dark surroundings were suitable conditions under which peanut sprouts were processed; neither factor significantly affected the allergenicity of Ara h1. These results provided a theoretical basis for studies using biological methods to reduce peanut allergenicity.     

Microwave-assisted extraction of phenolic antioxidant compounds from peanut skins

A microwave-assisted extraction system was used to extract phenolic antioxidants from peanut skins. The effects of microwave power (10%, 50%, 90% nominal), irradiation time (30, 90, 150 s) and sample mass (1.5, 2.5, 3.5 g) on total phenolic content (TPC), ORAC (oxygen radical absorbance capacity) level and resveratrol content of peanut skin extracts (PSE) were investigated. Peanut skins were extracted with 37.5 ml of 30% ethanol (EtOH) in water. A response surface method was used to estimate optimum extraction conditions, based on TPC, ORAC level and resveratrol content. The maximum predicted TPC, under the optimised conditions (90% microwave power, 30 s irradiation time and 1.5 g skins), was 143.6 mg gallic acid equivalent (GAE)/g skins. The highest ORAC value was 2789 μmol trolox equivalents (TE)/g skins, which occurred at 90% power, 150 s and 1.5 g of skins. Resveratrol was identified in PSE by LC–MS–MS analysis.     

Effects of heating method and temperature in combination with hypoxic treatment on γ-aminobutyric acid,phenolics content and antioxidant activity of germinated rice

Heat and hypoxic treatments were combined with soaking to enhance γ-aminobutyric acid (GABA) production in germinated paddy (GP). Effects of heating temperature, heating techniques, that is, impinging stream drying (ISD) and tray drying (TD), and germination time on the GABA content, phenolics content and antioxidant activity were also investigated. Heating temperature had a significant effect on the GABA content; both ISD and TD helped increase the GABA content when the post-treatment grain temperature was 38–40.5 °C. Within this grain temperature range, soaking in combination with heat and hypoxic treatments (S-ISD-H and S-TD-H) yielded GP with higher GABA content than soaking (S) and soaking in combination with hypoxic treatment (S-H). However, ISD was noted to be more suitable than TD. Phenolics content and antioxidant activity of GP prepared by S-ISD-H at different heating temperatures and S-H were not significantly different but were higher than those of the GP prepared by S.     

Characteristics of soybeans as affected by soaking conditions

The water absorption of soybeans in soaking is directly related to the changes in textural characteristics and grinding properties of soybeans for processing. In this study, we determined the characteristics of water absorption, solid loss, and moisture content, textural characteristics and grinding properties of soybeans at four different soaking temperatures, 10°C, 20°C, 30°C, and 40°C, and various soaking times up to 8 h. We found that the solid loss increased significantly when the soaking temperature increased from 30°C to 40°C. The measured moisture data of soaked soybeans fitted well with the data predicted using Peleg's equation. Rupture force and maximum tangent and secant modulus measured by the compression test decreased as the moisture increased, up to 122%. The grinding property of soaked soybeans was related only to the final moisture content and not to the soaking conditions. High soaking temperature could significantly reduce the required soaking time. Based on these results, we recommend that soybeans be soaked to minimal final moisture content of 120% before grinding.     

Characterization of Gamma Irradiated Peanut Kernels Stored One Year Under Ambient and Frozen Conditions

Peanut kernels were gamma irradiated at 0, 2.5,5.0,10, and 20 KGy, and stored 1 yr at ambient and frozen (? 14°C) conditions. Irradiated peanuts lost germination capabilities during storage. Molds were detected only on peanuts irradiated with 2.5 KGy and stored at ambient temperature. Peanut oil in kernels stored at ? 14°C was comparatively more stable than that in peanuts stored at ambient temperature. Oxidation of oil was not significantly changed by irradiation. Changes in fatty acid content varied slightly with exception of linoleic and linolenic acids which decreased with increased radiation depending on storage temperature. The SDS-PAGE protein patterns of peanuts revealed no noticeable variation of protein subunits resulting from irradiation and storage.     

The effect of light and temperature on glucosinolate concentration in the leaves and roots of cabbage seedlings

In previous studies it was shown that the concentration of total and individual glucosinolates in brassicaceous plants can vary significantly over a 24-h period grown either in the field or under controlled conditions. The present study shows total and individual glucosinolate variation during a single day. Seedlings of cabbage grown under controlled conditions and at 14 and 15 days after emergence were moved to 20°C (Exp A) and 30°C (Exp B), with a constant photosynthetic photon flux density of 480 μmol m⁻² s⁻¹ and 75% relative humidity, over a 2-day period, during which time aerial parts and roots were sampled at regular intervals. Whilst the glucosinolate patterns of the aerial part of the plant and of the roots remained the same, the levels of major glucosinolates in the aerial part, averaged over all sampling times and 2 days, were 233 ± 60 μmol 100 g⁻¹ DW for 3-methylsulphinylpropyl and 72 ± 22 for 2-propenyl; in the roots, 2-phenylethyl and 1-methoxyindol-3-ylmethyl showed the highest average concentrations, with 678 ± 355 μmol 100 g⁻¹ DW and 411 ± 122, respectively. Total and individual glucosinolate levels showed very high significant differences between the two plant parts. Despite the constant temperature, light and relative humidity, glucosinolates varied within a 24-h period, showing ultradian rhythms that are common to several metabolic processes in plants. The results confirm previous observations that at a temperature of 20°C, close to the optimum for growth and development, the diurnal variation in glucosinolate concentration, was smaller than at 30°C. © 1998 Society of Chemical Industry     

Survival of Lactobacillus rhamnosus GG as Influenced by Storage Conditions and Product Matrixes

Abstract: Mortality resulting from diarrhea especially that occurs in children younger than 5 y of age ranks 3rd among all deaths caused by infectious diseases worldwide. Probiotics such as Lactobacillus rhamnosus GG are clinically shown to effectively reduce the incidence of diarrhea in children. A food substrate is one of the major factors regulating the colonization of microorganisms in human gastrointestinal tracts. Peanut butter is a nutritious, low‐moisture food that could be a carrier for probiotics. In this study, we observed the influence of storage conditions and product matrixes on the survival of L. rhamnosus GG. Cells of L. rhamnosus GG were inoculated into full fat or reduced fat peanut butter at 10⁷ CFU/g. Inoculated peanut butter was stored at 4, 25, or 37 °C for 48 wk. Samples were drawn periodically to determine the populations of L. rhamnosus GG. Results showed that there was no significant decrease in the viable counts of L. rhamnosus GG in products stored 4 °C. The survivability of L. rhamnosus GG decreased with increasing storage temperature and time. Product matrixes did not significantly affect the survival of L. rhamnosus GG except at 37 °C. Populations of L. rhamnosus GG were preserved at >6 logs in products stored at 4 °C for 48 wk and at 25 °C for 23 to 27 wk. At 37 °C, the 6‐log level could not be maintained for even 6 wk. The results suggest that peanut butter stored at 4 and 25 °C could serve as vehicles to deliver probiotics. Practical Application: Lactobacillus rhamnosus GG is clinically shown to effectively reduce the incidence of diarrhea in children. A food substrate is one of the major factors regulating the colonization of microorganisms in human gastrointestinal tracts. Peanut butter is a nutritious, low‐moisture food that could be a carrier for probiotics. In this study, we demonstrated the influence of storage conditions and product matrixes on the survival of L. rhamnosus GG. Results suggest that peanut butters could be effective delivery systems for probiotics and that probitic peanut butter could be used as one of the strategies to control diarrhea and malnutrition in developing countries.     

Interactive effects of temperature and relative humidity on oviposition and development of Callosobruchus chinensis (L.) on azuki bean

The effects of three temperatures, 20 °C, 25 °C and 30 °C, and four relative humidity (RH) levels, 30–35%, 50–55%, 70–75%, and 90–95%, on oviposition and development of Callosobruchus chinensis (L.) (Coleoptera: Bruchidae) were investigated. C. chinensis were introduced to 30 g azuki bean seeds (cultivar Hongeon) one day post emergence. Five pairs of male and female beetles were used for each combination of temperature and RH, and replicated ten times. The introduced adults were allowed to lay eggs for 72 h. Temperature significantly influenced oviposition with increased number of eggs at 30 °C. Relative humidity had no effect on egg laying. Development time was affected by both temperature and RH. Development time was shortest at 30 °C and 70–75% RH. Adult emergence rate was affected by both temperature and RH; adult emergence rate increased with the increase in temperature and RH (up to 70–75%) levels. The results suggest that rather than the interactive effect of temperature and RH, individual effects of temperature and RH on C. chinensis are profound and C. chinensis is likely to cause greater damage to azuki bean seeds stored at 30 °C and 70–75% RH.     

Optimization of Polishing Conditions for Long Grain <Emphasis Type="Italic">Basmati</Emphasis> Rice in a Laboratory Abrasive Mill

Rice milling operation is a very energy-intensive process. The major qualities of the rice which are taken into consideration while milling are the degree of milling and head rice yield. A laboratory abrasion polisher, modified by attaching a humidifying and cooling unit, was used to polish long-grain Pusa Basmati rice in order to optimize the polishing conditions. Polishing experiments were carried out using central composite design for a factorial with a central point, at different initial grain temperatures (5–25 °C) and milling chamber temperatures (11–25 °C) at a constant humidity level of 95 ± 2% for different time intervals. Models capable of predicting the quality of milled rice were developed using response surface methodology and used to determine optimum processing conditions. Responses such as degree of milling (DOM), broken content, and specific energy consumption were used to assess product quality. Optimum milling conditions of a minimum of 10% DOM, a broken content of 8%, and a specific energy consumption of 11 kJ/DOM were obtained at a milling chamber temperature of 11 °C, an initial grain temperature of 15 °C, and a milling period of 180 s.     

Processing to Improve Quality of Dehydrated Precooked Pinto Beans

The firmness of precooked and rehydrated beans after soaking in water at 30°C/2 hr and 82°C/1 hr was lower than that after soaking at 82°C/1 hr or 22°C/12 hr. The 22°C/12 hr soaking yielded the lowest butterflying (8.0%). Steam precooking at 100°C/1 hr produced less splitting, lighter color, and firmer texture than pressure precooking. High initial humidity dehydration reduced splitting. Beans after soaking at 30°C/2 hr and 82°C/1 hr, precooking at 100°C/1 hr, and dehydrating at 65°C/6 hr with initial 95% relative humidity were better regarding firmness, butterflying (11.6%), and moisture content (10.4%).