Factors influencing the growth of Salmonella during sprouting of naturally contaminated alfalfa seeds

In this study, the factors that affect Salmonella growth during sprouting of naturally contaminated alfalfa seeds associated with two previous outbreaks of salmonellosis were examined. A minidrum sprouter equipped with automatic irrigation and rotation systems was built to allow sprouting to be conducted under conditions similar to those used commercially. The growth of Salmonella during sprouting in the minidrum was compared with that observed in sprouts grown in glass jars under conditions commonly used at home. The level of Salmonella increased by as much as 4 log units after 48 h of sprouting in jars but remained constant during the entire sprouting period in the minidrum. The effect of temperature and irrigation frequency on Salmonella growth was examined. Increasing the sprouting temperature from 20 to 30 degrees C increased the Salmonella counts by as much as 2 log units on sprouts grown both in the minidrum and in the glass jars. Decreasing the irrigation frequency from every 20 min to every 2 h during sprouting in the minidrum or from every 4 h to every 24 h during sprouting in the glass jars resulted in an approximately 2-log increase in Salmonella counts. The levels of total aerobic mesophilic bacteria, coliforms, and Salmonella in spent irrigation water closely reflected those found in sprouts, confirming that monitoring of spent irrigation water is a good way to monitor pathogen levels during sprouting.     

Anthocyanins,total polyphenols and antioxidant activity in amaranth and quinoa seeds and sprouts during their growth

Total antioxidant capacity, total phenolic contents (TP) and anthocyanins contents (ANT) were determined in Amaranthus cruentus and Chenopodium quinoa seeds and sprouts. Antioxidant activity of the investigated seeds decreased in the following order: quinoa, amaranth v. Rawa, amaranth v. Aztek for FRAP and quinoa, amaranth v. Aztek, amaranth v. Rawa for both ABTS and DPPH. Sprouts activity depended on the length of their growth, and the peak values were reached on the fourth day in the case of amaranth and on the sixth day in the case of quinoa. The data obtained by the three methods showed significant correlation between TP content in seeds and sprouts. In sprouts grown in the daylight and in the darkness we observed some significant changes of TP, ANT and antioxidant activity. Amaranth and quinoa seeds and sprouts can be used in food, because it is a good source of ANT and TP with high antioxidant activity.     

Growth of Salmonella during sprouting of alfalfa seeds associated with salmonellosis outbreaks

Growth of Salmonella was assessed during sprouting of naturally contaminated alfalfa seeds associated with two outbreaks of salmonellosis. Salmonella was determined daily in sprouts and sprout rinse water samples by a three-tube most probable number (MPN) procedure and a commercial enzyme immunoassay (EIA). Growth of Salmonella in the sprouts was reflected in the rinse water, and the MPNs of the two samples were generally in agreement within approximately 1 log. The results from EIA testing of sprouts and water samples were also in agreement. The pathogen was present in the seed at less than 1 MPN/g, and it increased in number to maximum population levels of 102 to 10(3) MPN/g in one seed lot and 10(2) to 10(4) MPN/ g in the other seed lot. Maximum populations of the pathogen were apparent by day 2 of sprouting. These results show the ability of the pathogen to grow to detectable levels during the sprouting process, and they provide support for the recommendation to test the sprout water for the presence of pathogens 48 h after starting seed sprouting. The effectiveness of a 10-min, 20,0000-microg/ml (ppm) calcium hypochlorite treatment of the outbreak-associated seeds was studied. For both seed lots, the hypochlorite treatment caused a reduction, but not elimination, of Salmonella contamination in the finished sprouts. These results confirm the need to test each production batch for the presence of pathogens, even after 20,000 microg/ml (ppm) hypochlorite treatment of seeds, so that contaminated product is not distributed.     

Alfalfa seed germination and yield ratio and alfalfa sprout microbial keeping quality following irradiation of seeds and sprouts.

Foods can be treated with gamma radiation, a nonthermal food process, to inactivate foodborne pathogens and fungi, to kill insects on or in fruits and vegetables, and to increase shelf life. Gamma irradiation is especially well suited for these treatments because of its ability to penetrate commercial pallets of foods. Irradiated fruits, vegetables, poultry, and hamburger have been received favorably by the public and are now available in supermarkets. The use of irradiation on fresh alfalfa sprouts was studied to determine its effect on keeping quality as related to aerobic microbial load. After an irradiation dose of 2 kGy, the total aerobic count decreased from 10(5-8) to 10(3-5) CFU/g, and the total coliform counts decreased from 10(5-8) to 10(3-0) CFU/g. The results showed that the sprouts maintained their structure after irradiation, and the keeping quality was extended to 21 days, which is an increase of 10 days from the usual shelf life. The effect of various doses of irradiation on alfalfa seeds as measured by percent germination and yield ratio (wt/wt) of sprouts was determined. There was little effect on the percent germination, but as the dose increased, the yield ratio of alfalfa sprouts decreased. As the length of growing time increased, so did the yield ratio of the lower dose irradiated seeds (1 to 2 kGy). The irradiation process can be used to increase the shelf life of alfalfa sprouts, and irradiating alfalfa seeds at doses up to 2 kGy does not unacceptably decrease the yield ratio for production of alfalfa sprouts.     

Efficacy of electrolyzed oxidizing water in inactivating Salmonella on alfalfa seeds and sprouts

Studies have demonstrated that electrolyzed oxidizing (EO) water is effective in reducing foodborne pathogens on fresh produce. This study was undertaken to determine the efficacy of EO water and two different forms of chlorinated water (chlorine water from Cl2 and Ca(OCl)2 as sources of chlorine) in inactivating Salmonella on alfalfa seeds and sprouts. Tengram sets of alfalfa seeds inoculated with a five-strain cocktail of Salmonella (6.3 x 10(4) CFU/g) were subjected to 90 ml of deionized water (control), EO water (84 mg/liter of active chlorine), chlorine water (84 mg/liter of active chlorine), and Ca(OCl)2 solutions at 90 and 20,000 mg/liter of active chlorine for 10 min at 24 +/- 2 degrees C. The application of EO water, chlorinated water, and 90 mg/liter of Ca(OCl)2 to alfalfa seeds for 10 min reduced initial populations of Salmonella by at least 1.5 log10 CFU/g. For seed sprouting, alfalfa seeds were soaked in the different treatment solutions described above for 3 h. Ca(OCl)2 (20,000 mg/liter of active chlorine) was the most effective treatment in reducing the populations of Salmonella and non-Salmonella microflora (4.6 and 7.0 log10 CFU/g, respectively). However, the use of high concentrations of chlorine generates worker safety concerns. Also, the Ca(OCl)2 treatment significantly reduced seed germination rates (70% versus 90 to 96%). For alfalfa sprouts, higher bacterial populations were recovered from treated sprouts containing seed coats than from sprouts with seed coats removed. The effectiveness of EO water improved when soaking treatments were applied to sprouts in conjunction with sonication and seed coat removal. The combined treatment achieved 2.3- and 1.5-log10 CFU/g greater reductions than EO water alone in populations of Salmonella and non-Salmonella microflora, respectively. This combination treatment resulted in a 3.3-log10 CFU/g greater reduction in Salmonella populations than the control (deionized water) treatment.     

Efficacy of benzyl isothiocyanate for controlling Salmonella on alfalfa seeds and sprouts

The efficacy of benzyl isothiocyanate (BIT), a compound found in cruciferous vegetables, for controlling Salmonella on alfalfa seeds and sprouts was investigated. Alfalfa seeds were inoculated by individual Salmonella enterica serotypes Newport, Typhimurium, Tennessee, Montevideo, or Braenderup at two inoculation levels of 3 or 5 log CFU g⁻¹, followed by treatment with BIT (0.5–2%) or chlorine (2%) for 15 min. Treated seeds were sprouted in seed sprouters. Surviving Salmonella populations on the seeds and sprouts were determined. At both inoculum levels, 1.5% and 2% of BIT significantly reduced populations S. Typhimurium and S. Braenderup on seeds to a level comparable to the chlorine-treated seeds. Salmonella populations recovered from the sprouts germinated from 1.5% or 2% BIT-treated seeds were significantly lower than the control and chlorine-treated seeds at both inoculum levels (P < 0.05). The results of the study indicate that BIT can be used to control Salmonella contamination on alfalfa seeds and subsequent sprouting process.     

Behavior of enterohemorrhagic Escherichia coli O157:H7 on alfalfa sprouts during the sprouting process as influenced by treatments with various chemicals.

The behavior of Escherichia coli O157:H7 on alfalfa seeds subjected to conditions similar to those used commercially to grow and market sprouts as it is affected by applications of NaOCl, Ca(OCl)2, acidified NaClO2, acidified ClO2, Na3PO4, Vegi-Clean, Tsunami, Vortexx, or H2O2 at various stages of the sprouting process was determined. Application of 2,000 ppm of NaOCl, 200 and 2,000 ppm of Ca(OCl)2, 500 ppm of acidified ClO2, 10,000 ppm of Vegi-Clean, 80 ppm of Tsunami, or 40 and 80 ppm of Vortexx to germinated seeds significantly reduced the population of E. coli O157:H7. With the exception of acidified NaOCl2 at 1,200 ppm, spray applications of these chemicals did not significantly reduce populations or control the growth of E. coli O157:H7 on alfalfa sprouts during the sprouting process. Populations of E. coli on alfalfa sprouts peaked at 6 to 7 log10 CFU/g 48 h after initiation of the sprouting process and remained stable despite further spraying with chemicals. The population of E. coli O157:H7 on sprouts as they entered cold storage at 9 +/- 2 degrees C remained essentially unchanged for up to 6 days. None of the chemical treatments evaluated was able to eliminate or satisfactorily reduce E. coli O157:H7 on alfalfa seeds and sprouts. Observations on the ability of E. coli O157:H7 to grow during production of alfalfa sprouts not subjected to chemical treatments are similar to those from a previous study in our laboratory on the behavior of Salmonella Stanley. Our results do not reveal a chemical treatment method to eliminate the pathogen from alfalfa sprouts. We have demonstrated that currently recommended procedures for sanitizing alfalfa seeds fail to eliminate E. coli O157:H7 and that the pathogen can grow to populations exceeding 7 1og10 CFU/g of sprouts produced using techniques not dissimilar to those used in the sprout industry.     

Efficacy of ozone in killing Listeria monocytogenes on alfalfa seeds and sprouts and effects on sensory quality of sprouts

A study was done to determine the efficacy of aqueous ozone treatment in killing Listeria monocytogenes on inoculated alfalfa seeds and sprouts. Reductions in populations of naturally occurring aerobic microorganisms on sprouts and changes in the sensory quality of sprouts were also determined. The treatment (10 or 20 min) of seeds in water (4 degrees C) containing an initial concentration of 21.8 +/- 0.1 microg/ml of ozone failed to cause a significant (P < or = 0.05) reduction in populations of L. monocytogenes. The continuous sparging of seeds with ozonated water (initial ozone concentration of 21.3 +/- 0.2 microg/ml) for 20 min significantly reduced the population by 1.48 log10 CFU/g. The treatment (2 min) of inoculated alfalfa sprouts with water containing 5.0 +/- 0.5, 9.0 +/- 0.5, or 23.2 +/- 1.6 microg/ml of ozone resulted in significant (P < or = 0.05) reductions of 0.78, 0.81, and 0.91 log10 CFU/g, respectively, compared to populations detected on sprouts treated with water. Treatments (2 min) with up to 23.3 +/- 1.6 microg/ml of ozone did not significantly (P > 0.05) reduce populations of aerobic naturally occurring microorganisms. The continuous sparging of sprouts with ozonated water for 5 to 20 min caused significant reductions in L. monocytogenes and natural microbiota compared to soaking in water (control) but did not enhance the lethality compared to the sprouts not treated with continuous sparging. The treatment of sprouts with ozonated water (20.0 microg/ml) for 5 or 10 min caused a significant deterioration in the sensory quality during subsequent storage at 4 degrees C for 7 to 11 days. Scanning electron microscopy of uninoculated alfalfa seeds and sprouts showed physical damage, fungal and bacterial growth, and biofilm formation that provide evidence of factors contributing to the difficulty of killing microorganisms by treatment with ozone and other sanitizers.     

Changes in colour and antioxidant activities of Hizikia fusiformis cooking drips by gamma irradiation

To utilize the cooking drips produced during the seaweed drying process, the effect of gamma irradiation on microbial contamination, colour, and antioxidant activities of Hizikia fusiformis cooking drips (HCD) was investigated. A two log cycles reduction of total aerobic bacteria and yeast and moulds counts was obtained irradiating HCD at 1 kGy. The Hunter L^∗ value of the HCD ethanol extract was increased by the gamma irradiation treatment, but the a^∗ and b^∗ values decreased upon irradiation depending on the absorbed dose. The 1,1-diphenyl-2-picrylhydrazyl radical scavenging and β-carotene bleaching activities of the HCD extracts increased as a result of gamma irradiation, which was rationalized by the observed increase in polyphenolic compounds content. These results suggest that wasted cooking drips can be used as a functional component by the food and cosmetic industries if the irradiation technology were applied.     

Inactivation of Escherichia coli O157:H7 and Salmonella by gamma irradiation of alfalfa seed intended for production of food sprouts

Inonizing irradiation was determined to be a suitable method for the inactivation of Salmonella and Escherichia coli O157:H7 on alfalfa seed to be used in the production of food sprouts. The radiation D (dose resulting in a 90% reduction of viable CFU) values for the inactivation of Salmonella and E. coli O157:H7 on alfalfa seeds were higher than the D-values for their inactivation on meat or poultry. The average D-value for the inactivation of Salmonella on alfalfa seeds was 0.97 +/- 0.03 kGy; the D-values for cocktails of meat isolates and for vegetable-associated isolates were not significantly different. The D-values for nonoutbreak and outbreak isolates of E. coli O157:H7 on alfalfa seeds were 0.55 +/- 0.01 and 0.60 +/- 0.01 kGy, respectively. It was determined that the relatively high D-values were not due to the low moisture content or the low water activity of the seed. The D-values for Salmonella on alfalfa seeds from two different sources did not differ significantly, even though there were significant differences in seed size and water activity. The increased moisture content of the seed after artificial inoculation did not significantly alter the D-value for the inactivation of Salmonella. The results of this study demonstrate that 3.3- and 2-log inactivations can be achieved with a 2-kGy dose of ionizing radiation, which will permit satisfactory commercial yields of sprouts from alfalfa seed contaminated with E. coli O157:H7 and Salmonella, respectively.     

Quantitative analysis of the growth of Salmonella stanley during alfalfa sprouting and evaluation of Enterobacter aerogenes as its surrogate

Raw seed sprouts have been implicated in several food poisoning outbreaks in the last 10 years. Few studies have included investigations of factors influencing the effectiveness of testing spent irrigation water, and in no studies to date has a nonpathogenic surrogate been identified as suitable for large-scale irrigation water testing trials. Alfalfa seeds were inoculated with Salmonella Stanley or its presumptive surrogate (nalidixic acid-resistant Enterobacter aerogenes) at three concentrations (-3, -30, and -300 CFU/g) and were then transferred into either flasks or a bench top-scale sprouting chamber. Microbial concentrations were determined in seeds, sprouts, and irrigation water at various times during a 4-day sprouting process. Data were fit to logistic regression models, and growth rates and maximum concentrations were compared using the generalized linear model procedure of SAS. No significant differences in growth rates were observed among samples taken from flasks or the chamber. Microbial concentrations in irrigation water were not significantly different from concentrations in sprout samples obtaihed at the same time. E. aerogenes concentrations were similar to those of Salmonella Stanley at corresponding time points for all three inoculum concentrations. Growth rates were also constant regardless of inoculum concentration or strain, except that lower inoculum concentrations resulted in lower final concentrations proportional to their initial concentrations. This research demonstrated that a nonpathogenic easy-to-isolate surrogate (nalidixic acid-resistant E. aerogenes) provides results similar to those obtained with Salmonella Stanley, supporting the use of this surrogate in future large-scale experiments.     

Evaluation of volatile chemical treatments for lethality to Salmonella on alfalfa seeds and sprouts

A study was done to evaluate natural volatile compounds for their ability to kill Salmonella on alfalfa seeds and sprouts. Acetic acid, allyl isothiocyanate (AIT), trans-anethole, carvacrol, cinnamic aldehyde, eugenol, linalool, methyl jasmonate, and thymol were examined for inhibitory and lethal activity against Salmonella by exposing inoculated alfalfa seeds to compounds (1,000 mg/liter of air) for 1, 3, and 7 h at 60 degrees C. Only acetic acid, cinnamic aldehyde, and thymol caused significant reductions in Salmonella populations (>3 log10 CFU/g) compared with the control (1.9 log10 CFU/g) after treatment for 7 h. Treatment of seeds at 50 degrees C for 12 h with acetic acid (100 and 300 mg/liter of air) and thymol or cinnamic aldehyde (600 mg/liter of air) significantly reduced Salmonella populations on seeds (>1.7 log10 CFU/g) without affecting germination percentage. Treatment of seeds at 50 degrees C with AIT (100 and 300 mg/liter of air) and cinnamic aldehyde or thymol (200 mg/liter of air) did not significantly reduce populations compared with the control. Seed germination percentage was largely unaffected by treatment with gaseous acetic acid, AIT, cinnamic aldehyde, or thymol for up to 12 h at 50 degrees C. The number of Salmonella on seeds treated at 70 degrees C for 80 min with acetic acid (100 and 300 mg/liter of air), AIT (100 mg/liter of air), and cinnamic aldehyde and thymol (600 mg/liter of air) at water activity (a(w)) 0.66 was not significantly different than the number inactivated on seeds at a(w) 0.49. Acetic acid at 200 and 500 mg/liter of air reduced an initial population of 7.50 log10 CFU/g of alfalfa sprouts by 2.33 and 5.72 log10 CFU/g, respectively, within 4 days at 10 degrees C. whereas AIT at 200 and 500 mg/liter of air reduced populations to undetectable levels; however, both treatments caused deterioration in sensory quality. Treatment of sprouts with 1 or 2 mg of AIT per liter of air adversely affected sensory quality but did not reduce Salmonella populations after 11 days of exposure at 10 degrees C.     

Microbial profiles of on-line--procured sprouting seeds and potential hazards associated with enterotoxigenic Bacillus spp. in homegrown sprouts

We examined the microbiological quality of sprouting seeds sold through the Internet. Overall, five types of seeds each from six organic and six conventional sources were evaluated. The growth and toxin production of naturally occurring Bacillus spp. in sprouts produced using home-scale sprouting devices also were investigated. For alfalfa, broccoli, lentil, mungbean, and radish seeds, the average microbial counts were 3.3, 4.0, 2.8, 3.5, and 3.6 log CFU/g, presumptive B. cereus counts were 0.7, 1.0, 0.8, 1.0, and 0.9 log CFU/g, and total coliform counts were -0.3, -0.4, -0.5, 0.0, and -0.4 log of the most probable number per gram, respectively. No Salmonella, Escherichia coli O157, other fecal coliforms, or Staphylococcus aureus was found on seeds. Compared with conventional seeds, the organic seeds had lower or equivalent counts for total microorganisms, presumptive B. cereus, and total coliforms. When seeds were sprouting using a glass jar, the growth of presumptive B. cereus was significant for radish and broccoli but not for alfalfa, lentil, and mungbean sprouts; the counts exceeded 5.0 log CFU/g in radish sprouts. When sprouts were grown using an automatic sprouting device, presumptive B. cereus showed slight growth (< 3.0 log cycles) in radish, broccoli, and mungbean sprouts but no growth in alfalfa and lentil sprouts. Although the presumptive B. cereus isolates were enterotoxigenic, they did not produce or accumulate detectable levels of diarrheal toxins in freshly produced sprouts.     

Changes in the body immunological status of peptic ulcer patients as affected by dietotherapy

The findings are presented characterizing the immunologic status of peptic ulcer patients during dietetic treatment. The immunologic shifts detected on admission to hospital (increased reactivity of T cells to specific antigen, immunoglobulin imbalance, changed concentrations of some complement components in the blood serum) were found to normalize under the effect of diets. The authors consider that dietetic treatment should be an obligatory component of the comprehensive management of peptic ulcer patients.     

Polyphenol composition and in vitro antioxidant activity of amaranth,quinoa buckwheat and wheat as affected by sprouting and baking

This study examined the polyphenol composition and antioxidant properties of methanolic extracts from amaranth, quinoa, buckwheat and wheat, and evaluated how these properties were affected following two types of processing: sprouting and baking. The total phenol content amongst the seed extracts were significantly higher in buckwheat (323.4 mgGAE/100 g) and decreased in the following order: buckwheat > quinoa > wheat > amaranth. Antioxidant capacity, measured by the radical 2,2-diphenyl-1-picylhydrazyl scavenging capacity and the ferric ion reducing antioxidant power assays was also highest for buckwheat seed extract (p < 0.01). Total phenol content and antioxidant activity was generally found to increase with sprouting, and a decrease in levels was observed following breadmaking. Analysis by liquid chromatography coupled with diode array detector revealed the presence of phenolic acids, catechins, flavanol, flavone and flavonol glycosides. Overall, quinoa and buckwheat seeds and sprouts represent potential rich sources of polyphenol compounds for enhancing the nutritive properties of foods such as gluten-free breads.     

Changes in cell-wall carbohydrates and lignin of some forage-type millets as affected by growth stage

Changes in the cell-wall carbohydrates and lignin of bajra (Pennisetum typhoides), jowar (Sorghum vulgare) and napier (Pennisetum purpureum)–bajra hybrids (NB₂₁) as affected by growth stage are reported. With growth of the plants the concentrations of α-cellulose and hemicellulose increased in the stems. In bajra and jowar this increase was gradual up to 60–70 days growth stage followed by a decline and a subsequent rise towards maturity. In contrast, in NB₂₁, α-cellulose continued to rise gradually throughout the growth period. The concentration of hemicellulose was much higher in the stems than in the leaves of NB₂₁. With the ageing of the plants the lignin content increased in all these forage crops. In NB₂₁ the stems contained more lignin than the leaves at all stages of maturity. Fluctuations in the contents of lignin, cellulose and hemicellulose followed similar trends indicating that possibly they are components of a common matrix in the cell wall. In NB₂₁ the water-soluble carbohydrates continued to rise throughout the growth period unlike other forage crops. The protein content decreased as the NB₂₁ plants matured. The protein content of the leaves of these plants was always higher than that of the stems. The oxalates gradually declined with the maturation of the plants.     

Structural feature and antioxidant activity of low molecular weight laminarin degraded by gamma irradiation

Recently, it has been reported that low molecular weight laminarin had enhanced biological activities. In this study, laminarin was degraded by gamma irradiation, and the changes in its structure and antioxidant property were investigated. Gel permeation chromatography data showed that the average molecular weight of the irradiated laminarin decreased significantly as the irradiation dose increased. The absorbance at 290 nm, from UV spectra, was increased, depending on the irradiation dose and caused by the formation of carbonyl groups. From the NMR analysis, the ratio of β-1,3- to β-1,6-linkages was not changed, indicating the random scission of chains by gamma irradiation. The antioxidative activities, measured by Rancimat test, were all increased in the gamma-irradiated laminarin, depending on the absorbed dose, presumably due to the carbonyl groups formed by gamma irradiation. Therefore, gamma irradiation could be a promising method for preparing low molecular weight laminarin with enhanced biological activities.     

Treatment of Escherichia coli O157:H7 inoculated alfalfa seeds and sprouts with electrolyzed oxidizing water

Electrolyzed oxidizing water is a relatively new concept that has been utilized in agriculture, livestock management, medical sterilization, and food sanitation. Electrolyzed oxidizing (EO) water generated by passing sodium chloride solution through an EO water generator was used to treat alfalfa seeds and sprouts inoculated with a five-strain cocktail of nalidixic acid resistant Escherichia coli O157:H7. EO water had a pH of 2.6, an oxidation-reduction potential of 1150 mV and about 50 ppm free chlorine. The percentage reduction in bacterial load was determined for reaction times of 2, 4, 8, 16, 32, and 64 min. Mechanical agitation was done while treating the seeds at different time intervals to increase the effectiveness of the treatment. Since E. coli O157:H7 was released due to soaking during treatment, the initial counts on seeds and sprouts were determined by soaking the contaminated seeds/sprouts in 0.1% peptone water for a period equivalent to treatment time. The samples were then pummeled in 0.1% peptone water and spread plated on tryptic soy agar with 5 microg/ml of nalidixic acid (TSAN). Results showed that there were reductions between 38.2% and 97.1% (0.22-1.56 log(10) CFU/g) in the bacterial load of treated seeds. The reductions for sprouts were between 91.1% and 99.8% (1.05-2.72 log(10) CFU/g). An increase in treatment time increased the percentage reduction of E. coli O157:H7. However, germination of the treated seeds reduced from 92% to 49% as amperage to make EO water and soaking time increased. EO water did not cause any visible damage to the sprouts.     

不同生长期花生芽中主要营养成分变化

对发芽至不同时期的花生芽中营养成分含量的变化进行了研究.结果表明,发芽后花生籽仁中的主要营养成分及其含量发生了不同程度的变化:生长5d的花生芽中蛋白质、游离氨基酸和Vc含量分别为48.75％干重(DW)、0.59％ DW和21.53mg· 100g 1鲜重(FW),显著高于未发芽时的含量(p＜0.05),其中V c含量与发芽时间显著正相关(p＜0.05);脂肪含量为27.25％ DW,显著低于未发芽时的含量(p＜0.05);脂肪酸组成中亚油酸、亚麻酸所占比例较未发芽时降低,油酸比例增加:氨基酸组成中总必需氨基酸含量略有降低,但是总必需氨基酸与总氨基酸的比值基本没变;单糖组成中半乳糖醛酸含量、葡萄糖含量和阿拉伯糖含量显著增加(p＜0.05).