The Effectiveness of Antibrowning Dip Treatments to Reduce After‐Cooking Darkening in Potatoes

Abstract: After‐cooking darkening (ACD) is an inherent and undesirable trait that develops in cooked potatoes. The objective of this study was to evaluate the effectiveness of sodium acid sulfate (SAS) dip treatments compared to other antigraying treatments and a control to reduce ACD in boiled, Katahdin potatoes. Dip treatments were applied for 3 min prior to boiling and included: 3% SAS, 3% citric acid (CA), 3% sodium acid pyrophosphate (SAPP), along with a distilled water control. SAS‐ and CA‐treated potatoes had slightly, but significantly (P ≤ 0.05) higher b* and chroma values, which indicates a more intense yellow potato color, with less graying, compared to the control. SAS‐ and CA‐treated potatoes also had significantly (P≤ 0.001) lower pH values for inner and outer potato surfaces than the control. No significant (P > 0.05) differences were detected for total phenolic or mineral contents among treatments. CA and SAPP samples had slightly, but significantly (P≤ 0.05) higher moisture contents than the control. Sensory test results showed no significant differences for color, aftertaste, or overall acceptability. However, CA‐treated samples were rated significantly (P≤ 0.05) lower for flavor than all other treatments and panelists commented on sour notes. CA‐ and SAS‐treated potatoes were scored slightly, but significantly lower for texture than other treatments due to a waxy outer layer. However, SAS was the most acidic dip treatment, but did not significantly affect flavor. Overall, results suggest that SAS was similarly accepted by consumers in comparison to CA and SAPP, which is the industry standard to reduce ACD. Practical Application: After‐cooking darkening (ACD) is an undesirable potato trait that occurs after potatoes have been processed. Sodium acid pyrophosphate (SAPP) has been used as the industry standard to reduce ACD. Sodium acid sulfate (SAS) treatments prior to boiling appeared to be comparable to SAPP and citric acid in effectiveness to reduce ACD. SAS did not negatively affect the flavor of boiled potato samples according to sensory results. The SAS treatment may be more beneficial for potatoes intended for potato salad products.     

The effectiveness of ozone and acidulant treatments in extending the refrigerated shelf life of fresh-cut potatoes

Abstract: The objective of the study was to determine the effectiveness of acidulant dip treatments (with or without aqueous ozone) to reduce enzymatic browning and to extend the shelf life of fresh‐cut potato slices during refrigerated storage (4 °C) for 28 d. Potato slices subjected to aqueous ozone (2 ppm) had significantly (P≤ 0.05) higher L‐values and lower a‐values, but ozone did not appear to have any effect on aerobic plate counts (APCs) or polyphenol oxidase (PPO) activity. NatureSeal (NS) and sodium acid sulfate (SAS) were the most effective acidulant treatments in reducing browning (significantly [P≤ 0.05] higher L‐values, lower a‐values, and browning index values) regardless of ozone treatment. NS and SAS also had lower PPO activity compared to other treatments on days 0 and 28, and significantly (P≤ 0.05) lower APCs (≤2.00 log CFU/g) over refrigerated storage. Therefore, the SAS treatment was comparable to NS, a commercially available product, and showed promise as an effective antibrowning dip to reduce browning and spoilage in fresh‐cut potato products. Practical Application: A 1% SAS dip treatment which included 1% citric and 1% ascorbic acid was found to be an effective antibrowning dip for fresh‐cut potatoes along with NatureSeal®'s PS‐10, compared to other treatments. They were both effective in maintaining low microbial counts over refrigerated storage. Additionally, aqueous ozone washes (2 ppm) showed significant benefits to reduce browning; however, ozone did not affect microbial counts or PPO enzyme activity. Therefore, the SAS treatment could have potential use in the fruit and vegetable industry to reduce browning and spoilage in fresh‐cut potato products.     

The Effect of Antibrowning Agents on Inhibition of Potato Browning,Volatile Organic Compound Profile,and Microbial Inhibition

Abstract: Burbank and Norkotah potato slices were dipped into 3% sodium acid sulfate (SAS), citric acid (CA), sodium erythorbate (SE), malic acid (MA), sodium acid pyrophosphate (SAPP), or a combination of SAS‐CA‐SE. Browning by polyphenol oxidase (PPO) obtained from potato extract with 0.04 to 0.016 g/mL of antibrowning solutions at pH 2.0 to 6.9 were measured by UV‐Vis spectroscopy. The color of slices dipped in antibrowning solutions at pHs 2 to 7 and stored at 4 °C for 15 d was measured every 5 d by colorimeter. Headspace analysis of volatiles in raw and cooked potato samples was performed by selected ion flow tube mass spectrometer (SIFT‐MS) and soft independent modelling by class analogy (SIMCA) analysis of the calculated odor activity values (OAV) determined interclass distances. Microbial growth was measured at 15 d. At unadjusted pHs (1.1 to 7.1), the PPO browning of the control and samples with SAPP was not significantly different, SAS, CA, and MA produced some inhibition and SE and SAS‐CA‐SE prevented browning. At pH 5 to 7, only SE and SAS‐CA‐SE were effective browning inhibitors. Based on the color of potato slices, SE was the most effective at pH 2 to 7, but SAS was most effective at unadjusted pH. Cooking increased volatile levels in the treated potatoes and decreased differences between volatile profiles. Differences between cooked samples may not be noticeable by the consumer because volatiles with high discriminating powers have low OAVs. SAS, CA, and SAS‐CA‐SE treatments inhibited microbial growth but SAPP, control, and SE did not, most likely due to pH. Practical Application: Antibrowning agents inhibit polyphenol oxidase, increasing shelf life and consumer acceptability of processed raw potato products by preserving the color. Their effectiveness was shown to be mainly due to a pH effect, except SE, which was not pH dependent. MA, CA, and SAS‐CA‐SE are better acidulants for inhibition of color change as well as growth of spoilage bacteria, yeast, and mold than SAPP, the industry standard.     

Antibrowning and Antimicrobial Properties of Sodium Acid Sulfate in Apple Slices

ABSTRACT: There are few available compounds that can both control browning and enhance microbial safety of fresh‐cut fruits. In the present study, the antibrowning ability of sodium acid sulfate (SAS) on “Granny Smith” apple slices was first investigated in terms of optimum concentration and treatment time. In a separate experiment, the apple slices were treated with water or 3% of SAS, calcium ascorbate, citric acid, or acidified calcium sulfate for 5 min. Total plate count, color, firmness, and tissue damage were assessed during a 21‐d storage at 4 °C. Results showed that the efficacy of SAS in inhibiting browning of apple slices increased with increasing concentration. A minimum 3% of SAS was needed to achieve 14 d of shelf life. Firmness was not significantly affected by SAS at 3% or lower concentrations. Antibrowning potential of SAS was similar for all treatment times ranging from 2 to 10 min. However, SAS caused some skin discoloration of apple slices. When cut surface of apple slices were stained with a fluorescein diacetate solution, tissue damage could be observed under a microscope even though visual damage was not evident. Among the antibrowning agents tested, SAS was the most effective in inhibiting browning and microbial growth for the first 14 d. Total plate count of samples treated with 3% SAS was significantly lower than those treated with calcium ascorbate, a commonly used antibrowning agent. Our results suggested that it is possible to use SAS to control browning while inhibiting the growth of microorganisms on the apple slices if the skin damage can be minimized. Practical Application: Fresh‐cut apples have emerged as one of the popular products in restaurants, schools, and food service establishments as more consumers demand fresh, convenient, and nutritious foods. Processing of fresh‐cut apples induces mechanical damage to the fruit and exposes apple tissue to air, resulting in the development of undesirable tissue browning. The fresh‐cut industry currently uses antibrowning agents to prevent discoloration. However, the antibrowning solutions can become contaminated with human pathogens such as Listeria monocytogenes, and washing of apple slices with the contaminated solutions can result in the transfer of pathogens to the product. It would be ideal if an antibrowning compound prevented the proliferation of human pathogens in solutions and minimized the growth of pathogens during storage. The study was conducted to investigate antibrowning and antimicrobial properties of sodium acid sulfate (SAS) in comparison with other common antibrowning agents on Granny Smith apples. Results showed that among the antimicrobial agents we tested, SAS was the most effective in inhibiting browning and microbial growth for 14 d at 4 °C. However, SAS caused some skin discoloration of apple slices. Overall, SAS can potentially be used to inhibit tissue browning while reducing the microbial growth on apple slices. The information is useful for the fresh‐cut produce industry to enhance microbial safety of fresh‐cut apples while minimizing browning, thus increasing the consumption of the health benefiting fresh fruit.     

Changes of mutagenicity and antimutagenicity of the lactic fermented soymilk after exposure to acid,bile salt and heating

BACKGROUND: Fermented soymilk, prepared with co‐culture of Streptococcus thermophilus and Bifidobacterium infantis, possessed enhanced antioxidant and antimutagenic activities. Considering the possible alternation in functional properties, the mutagenicity and antimutagenicity of the prepared fermented soymilk against 4‐nitroquinoline‐N‐oxide (4‐NQO) and 3,2′‐dimethyl‐4‐aminobiphenyl (DMAB) as influenced by acid (pH 2.0), bile salt and heat treatments were investigated using the Ames test. RESULTS: Untreated‐ and treated‐fermented soymilk showed no mutagenic activity. After exposure to a pH of 2.0 for 20 or 60 min, the antimutagenicity of the fermented soymilk on 4‐NQO and DMAB decreased, while still possessing ca 25.9–33.9% and 61.8–67.9%, respectively, of its original activity. Exposure of fermented soymilk to 1% bile salt resulted in a 10.8% reduction, and no reduction of antimutagenicity, against 4‐NQO and DMAB, respectively. Heating the fermented soymilk at 55 °C or higher for 10 min caused a significant reduction in antimutagenicity on DMAB, while the antimutagenicity against 4‐NQO remained stable until the temperature was raised to 65 °C. CONCLUSION: The fermented soymilk still possessed antimutagenicity after exposure to all the treatments examined. This further demonstrates the potential utilization of fermented soymilk as an ingredient in the preparation of healthy foods. Copyright © 2008 Society of Chemical Industry     

The Quality Changes of Postharvest Mulberry Fruit Treated by Chitosan‐g‐Caffeic Acid during Cold Storage

This study aimed to characterize the effects of chitosan‐g‐caffeic acid (CTS‐g‐CA) on improving the quality and extending the shelf life of postharvest mulberry fruit during storage at 4 °C for 18 d. CTS‐g‐CA was enzymatically synthesized using laccase from Pleurotus ostreatus as a catalyst. The synergistic effects of CTS‐g‐CA treatment on mulberry fruit were evaluated using a co‐toxicity factor (cf). The results showed that the rotting rate of CTS‐g‐CA‐treated fruit was 37.67% (compared with that of the control at 97.67%) on day 18. The weight loss and malondialdehyde (MDA) contents of the CTS‐g‐CA‐treated mulberry fruit were significantly lower (P < 0.05) than those of the control, CA, CTS, and CA+CTS treatments. Moreover, the DPPH and ABTS radical scavenging activities of the CTS‐g‐CA treatment were both higher than those of the control. Furthermore, the CTS‐g‐CA treatment also maintained higher levels of main active substances, such as anthocyanins, ascorbic acid, polyphenols and flavones, in mulberry fruit than the other treatments. Therefore, CTS‐g‐CA could be used to improve the quality and extend the shelf life of postharvest mulberry fruit during cold storage.     

Anti‐glycative and anti‐inflammatory effects of caffeic acid and ellagic acid in kidney of diabetic mice

Protective effects of caffeic acid (CA) and ellagic acid (EA) in kidney of diabetic mice were examined. CA or EA at 2.5 and 5% was mixed in diet and supplied to diabetic mice for 12 wk. Results showed that the intake of CA or EA increased renal content of these compounds, alleviated body weight loss, decreased urine output, increased plasma insulin and decreased blood glucose levels at weeks 6 and 12 (p<0.05). The intake of these compounds dose dependently reduced plasma blood urea nitrogen and elevated creatinine clearance (p<0.05). CA or EA at 5% significantly decreased the levels of plasma HbA1c, urinary glycated albumin, renal carboxymethyllysine, pentosidine, sorbitol and fructose (p<0.05), and significantly diminished renal activity of aldose reductase and sorbitol dehydrogenase, as well as suppressed renal aldose reductase mRNA expression (p<0.05). CA or EA dose dependently lowered renal levels of IL‐6, IL‐1β, tumor necrosis factor (TNF)‐α and monocyte chemoattractant protein 1 (MCP‐1) (p<0.05). Furthermore, CA or EA dose dependently down‐regulated tumor necrosis factor‐α and monocyte chemoattractant protein‐1 mRNA expression in kidney (p<0.05). Based on the observed anti‐glycative and anti‐inflammatory effects, the supplement of CA or EA might be helpful for the prevention or attenuation of diabetic kidney diseases.     

Comparison of calcium lactate with chlorine as a washing treatment for fresh‐cut lettuce and carrots: quality and nutritional parameters

The efficacies of calcium lactate and chlorine washing treatments of fresh‐cut lettuce and carrots were compared during storage at 4 °C over 10 days. The gas composition of packages, colour, enzyme activity, texture, sensory attributes, microflora and levels of ascorbic acid and carotenoids were evaluated at 1, 3, 7 and 10 days. Calcium lactate treatment was not significantly different to chlorine treatment (p < 0.05) in terms of maintaining colour, texture and acceptability of fresh‐cut lettuce and carrots during the entire storage period. The washing treatments did not affect levels of ascorbic acid of fresh‐cut lettuce or carrots. Carotenoid levels were higher in calcium lactate‐treated carrots than chlorine‐treated samples at the end of storage. Mesophilic, psychrotrophic and lactic acid bacteria counts were not significantly different between treatments for both vegetables. Copyright © 2005 Society of Chemical Industry     

Intravaginal instillation of gonadotropin-releasing hormone analogues with an absorption enhancer induced a surge of luteinizing hormone in lactating dairy cows

Our objectives were to evaluate circulating LH concentrations after intravaginal (IVG) instillation of GnRH analogs in lactating dairy cows. In 2 experiments, lactating Holstein cows (experiment 1: n = 32; experiment 2: n = 47) received the experimental treatments 48 h after the first of 2 PGF_2α treatments given 12 h apart and 7 d after a modified Ovsynch protocol (GnRH at ?7 d, PGF_2α at ?24 h, PGF_2α at ?56 h, GnRH at 0 h). In experiment 1, cows were stratified by parity and randomly allocated to receive the following treatments: 2 mL of saline IVG (SAL, n = 6), 100 µg of gonadorelin (Gon) i.m. (G100-IM, n = 5), and 100 (G100, n = 7), 500 (G500, n = 8), or 1,000 µg of Gon IVG (G1000, n = 7). In experiment 2, treatments were SAL (n = 8), G100-IM (n = 8), G1000 (n = 7), 1,000 µg of Gon plus 10% citric acid (CA) IVG (G1000CA, n = 8), 80 µg of buserelin IVG (B80, n = 8), and 80 µg of buserelin plus 10% CA IVG (B80CA, n = 8). In both experiments, blood was collected every 15 min from ?15 min to 4 h, and every 30 min from 4 to 6 h after treatment. Data for area under the curve (AUC), mean LH concentrations, and time to maximum LH concentration were analyzed by ANOVA with (mean LH only) or without repeated measures using PROC MIXED of SAS (version 9.4, SAS Institute Inc., Cary, NC). The proportion of cows with a surge of LH was evaluated with Fisher's exact test using PROC FREQ of SAS. In both experiments, LH concentrations were affected by treatment, time, and the treatment by time interaction. In experiment 1, the AUC for LH and maximum LH concentration were greatest for the G100-IM treatment and were greater for the G1000 than for the SAL and G500 treatments. The proportion of cows with an observed surge of LH was 100 and 0% for cows that received Gon i.m. and IVG, respectively. In experiment 2, the AUC and maximum LH concentrations were greater for the G100-IM, G1000CA, and B80CA treatments than for the other IVG treatments. The proportion of cows with a surge of LH differed by treatment (SAL = 0%, G100-IM = 100%, G1000 = 14%, G1000CA = 88%, B80 = 13%, and B80CA = 100%). For the treatments with a surge of LH, time to maximum concentration of LH was the shortest for the G100-IM treatment, intermediate for the G1000CA treatment, and the longest for cows in the B80CA treatment. In conclusion, Gon (up to 1,000 µg) absorption through intact vaginal epithelium after a single IVG instillation was insufficient to elicit a surge of LH of normal magnitude. Conversely, IVG instillation of 1,000 µg of Gon and 80 µg of buserelin with the addition of citric acid as absorption enhancer resulted in a surge of LH of similar characteristics than that induced after i.m. injection of 100 µg of Gon.     

Channel catfish (Ictalurus punctatus) muscle protein isolate performance processed under different acid and alkali pH values

Abstract: Channel catfish (Ictalurus punctatus) muscle was subjected to 6 protein extraction and precipitation techniques using acid solubilization (pH 2.0, 2.5, and 3.0) or alkaline solubilization (pH 10.5, 11.0, 11.5) followed by precipitation at pH 5.5. The catfish protein isolate was compared with ground defatted white muscle. Alkali‐processed catfish showed increased gel rigidity, gel strength, and gel flexibility compared to acid‐processed catfish, which exhibited inconsistent functional performance, increasing and decreasing gel rigidity, gel strength, and gel flexibility. The gel rigidity (G′) at pH 3.0 in the absence of salt had the highest G′ of the acid treatments and was not significantly different from the alkaline‐treated catfish muscle (P > 0.05). However in the presence of added salt pH treatment it had the lowest G′ and was different from alkaline treatments (P < 0.05) during break force testing. These results show that pH‐shift processing of channel catfish muscle provides highly functional isolates with a potentially broad range of applications. This range of applications is possible due to the modification of the textural properties of catfish muscle protein produced using different acidic or alkaline pH solubility treatments.     

Effects of 1‐methylcyclopropene and post‐controlled atmosphere air storage treatments on fresh‐cut Ambrosia apple slices

BACKGROUND: The effect of 1‐methylcyclopropene (1‐MCP) treatment and two different post‐controlled atmosphere air storage (PCAAS) durations on the quality and chemistry of fresh‐cut Ambrosia apple slices was studied. RESULTS: PCAAS for 1 or 2 weeks prior to slicing had an overall positive effect on the resultant quality of fresh‐cut apple slices. The most significant responses to PCAAS were the suppression of both phenolic and o‐quinone accumulation in slices, and this was related to the significantly lower browning potential values obtained for slices from PCAAS‐treated apples. Polyphenol oxidase (PPO), peroxidase (POX) and ascorbate peroxidase (APOX) activities were not affected by 1‐MCP or PCAAS treatments. PPO and POX activities were almost completely inhibited by a 50 g L^?1 calcium ascorbate anti‐browning dip of apple slices from all treatments. CONCLUSION: The most dramatic effect of the PCAAS treatments was to reduce the accumulation of soluble phenolics, which is likely the reason that o‐quinone accumulation was also inhibited in treated fruits. The consequent reduction in browning potential may be the explanation as to why PCAAS treatment has been shown to reduce fresh apple slice browning in previous work. Copyright © 2012 Society of Chemical Industry     

Heated Ascorbic/Citric Acid Solution as Browning Inhibitor for Pre-Peeled Potatoes

Treatment of pre-peeled potatoes with heated ascorbic acid (AA)/citric acid (CA) solution to extend shelf-life was investigated. Potatoes were abrasion or high pressure steam peeled, heated for 5–20 min in 1% AA + 2% CA at 45–55°C cooled, and then dipped for 5 min in browning inhibitor (BI) solution containing 4% AA +1% CA +1% sodium acid pyrophosphate. Combined treatment inhibited potato discoloration for 14 days at 4°C compared to 3–6 days with BI treatment alone. Raw material and treatment conditions were selected to minimize graying and textural abnormalities encountered with some treatments. Treatment with heated AA/CA may be an alternative to use of sulfites to control browning in pre-peeled potatoes.     

Combination of 1-methylcyclopropene treatment and controlled atmosphere storage retains overall fruit quality and bioactive compounds in mango

BACKGROUND: Postharvest application of fungicide prochloraz and hot‐water dip are commercially practiced to control postharvest diseases in mangoes. Owing to the increasing consumer demand for organically produced fruit, the search for natural environmentally friendly alternative products and processes has become important for the fruit industry. This study evaluated the combined effect of 1‐methylcyclopropene (1‐MCP) (500 nL L^?1) and controlled atmosphere storage conditions (CA‐1, 5% O₂ + 5% CO₂ or CA‐2, 3% O₂ + 8% CO₂) on the maintenance of fruit quality and bioactive compounds on hot‐water treated mangoes (cv. Kent) during postharvest storage. RESULTS: In comparison to the 1‐MCP + CA‐1 treatment, 1‐MCP + CA‐2 reduced the incidence of anthracnose, weight and firmness loss; delayed the skin and flesh colour development; prevented the increase of soluble solids concentration/titratable acidity ratio, ethanol and acetaldehyde content; and maintained the ascorbic acid, carotenoid, total phenolic and flavonoid contents, and antioxidant scavenging activity in hot‐water treated mangoes. The untrained panel preferred 1‐MCP + CA‐2 treated fruit to the fruit subjected to other postharvest treatments adopted in this investigation. CONCLUSION: Our investigation suggests that the combined effect of 1‐MCP and CA‐2 storage can be recommended as an alternative treatment to replace prochloraz application for hot‐water treated mangoes and can be adopted commercially for organic export markets. Copyright © 2011 Society of Chemical Industry     

Combined Effects of Alkaline Electrolyzed Water and Citric Acid with Mild Heat to Control Microorganisms on Cabbage

ABSTRACT: Effects of alkaline electrolyzed water (AlEW), acidic electrolyzed water (AcEW), 100 ppm sodium hypochlorite (NaClO), deionized water (DIW), 1% citric acid (CA) alone, and combinations of AlEW with 1% CA (AlEW + CA), in reducing the populations of spoilage bacteria and foodborne pathogens on cabbage were investigated at various dipping times (3, 5, and 10 min) with different dipping temperatures (1, 20, 40, and 50 °C). Inhibitory effect of the selected optimal treatment against Listeria monocytogenes and Escherichia coli O157 : H7 on cabbage were also evaluated. Compared to the untreated control, AlEW treatment most effectively reduced the numbers of total bacteria, yeast, and mold, followed by AcEW and 100-ppm NaClO treatments. All treatments dip washed for 5 min significantly reduced the numbers of total bacteria, yeast, and mold on cabbage. With increasing dipping temperature from 1 to 50 °C, the reductions of total bacteria, yeast, and mold were significantly increased from 0.19 to 1.12 log CFU/g in the DIW wash treatment (P < 0.05). Combined 1% CA with AlEW treatment at 50 °C showed the reduction of around 3.98 and 3.45 log CFU/g on the total count, and yeast and mold, effective reduction of L. monocytogenes (3.99 log CFU/g), and E. coli O157 : H7 (4.19 log CFU/g) on cabbage. The results suggest that combining AlEW with CA could be a possible method to control foodborne pathogens and spoilage bacteria effectively on produce.     

Performance,carcass cut‐up and fatty acids deposition in broilers fed different levels of pellet‐processed flaxseed

The effects of flaxseed (FS) processing and inclusion levels on broiler performance and fatty acid deposition were examined. FS was provided as whole seed, ground or pellet‐then‐mashed at a dietary level of 0, 12 or 14% during days 1 to 21. These levels represented control, threshold and over‐threshold, respectively. During days 22 to 40, the threshold level was increased to 15%, while the over‐threshold level increased to 17%. After 21 days of feeding, the performance of birds fed a diet with 12% pellet‐then‐mashed FS were comparable (p > 0.05) with those fed mashed control diet, but superior to those fed a diet of whole FS (p < 0.05). There was interaction (p < 0.05) between diet processing and FS level on weight gain, with pellet‐then‐mash processing being more effective at the 12% FS inclusion level than at the 14% level in improving performance. The beneficial processing effect on performance diminished during days 22 to 40. Furthermore, carcass cut‐up percentage was not affected (p > 0.05) by the treatments, except that increased FS level resulted in smaller fat‐pad and larger liver (p < 0.05). Birds deposited omega‐3 (n‐3) fatty acids in breast and thigh muscle the most with higher FS inclusion and pellet‐then‐mash processing. On day 40, the total n‐3 fatty acids made up 22.1 and 24.4% in the muscle lipids of breast and thigh samples from birds fed pellet‐then‐mashed FS at the level of 12% during days 1 to 21 and at the level of 15% during days 22 to 40, respectively. These values were higher (p < 0.05) than those found in birds fed diets of similar FS levels but as whole seed or ground seed. Up to 12% pellet‐processed FS can be incorporated into broiler diets with satisfactory growth, while maximizing n‐3 fatty acid deposition in the tissues. Copyright © 2005 Society of Chemical Industry     

Plasma phospholipids n‐3 polyunsaturated fatty acid is associated with metabolic syndrome

The relationship between n‐3 PUFA and metabolic syndrome (MS) is not clear. The aim of this study was to examine relationships between plasma phospholipids (PL) n‐3 PUFA and MS in Chinese subjects. Nine hundred and twenty‐nine subjects were recruited in Hangzhou, China. Two hundred and ten (183 males, 27 females) with MS and 719 (545 males, 174 females) healthy subjects were identified in this cross‐sectional study. The prevalence of MS in females (24.56%) was significantly higher than that in males (10.04%) in this population. Total PUFA (p<0.001), n‐3 PUFA (p<0.001), and n‐3:n‐6 (p<0.001) were significantly lower in MS subjects compared to healthy subjects. Plasma phospholipid (PL), n‐3 PUFA was significantly inversely associated with MS (p=0.013). In addition, subjects with high levels of PL total fatty acids (FA) had a more than threefold higher likelihood of MS (OR=3.44, 95% CI=1.60–7.39) than the subjects with low levels of PL total FA. Our results suggest that plasma PL n‐3 PUFA was significantly inversely associated with MS, while high total FA were positively associated with MS in Chinese.     

Comparative potential of white and red clover to modify the milk fatty acid profile of cows fed ryegrass‐based diets from zero‐grazing and silage systems

BACKGROUND: Two experiments were conducted to compare the effects of white and red clover on the fatty acid composition of milk fat from cows fed ryegrass‐based diets. In experiment 1, fresh ryegrass was mixed with white or red clover (60/40, on a dry matter (DM) basis). Experiment 2 involved similar mixed diets in ensiled form, and one ryegrass‐silage diet without the addition of clover. RESULTS: Total DM intake, milk yield and milk fat content were not affected by dietary treatments. Feeding freshly cut white versus red clover supplemented diets resulted in a higher proportion of n‐3 fatty acids, especially α‐linolenic acid, in milk fat. Addition of any clover silage to ryegrass silage increased the proportions of n‐3 fatty acids in milk fat, and reduced the proportions of conjugated linoleic acids (CLA), including C18:2 c9t11, and C18:1cis isomers. The n‐6/n‐3 ratio was elevated compared to the diet not supplemented with clover. CONCLUSION: White clover seemed to be slightly superior to red clover supplementation, but the effects of clover supplementation as such were generally larger than that of clover type. However, a higher concentration of n‐3 fatty acids with clover supplementation coincided with a lower concentration of CLA in the milk fat. Copyright © 2007 Society of Chemical Industry     

EFFICACY OF SOUR WHEY AS A SHELF‐LIFE ENHANCER: USE IN ANTIOXIDATIVE EDIBLE COATINGS OF CUT VEGETABLES AND FRUIT*

ABSTRACT

The effectiveness of edible coatings containing sour whey powder (SWP), compared with soy protein isolate (SPI) and calcium caseinate (CC), in reducing oxidative browning and moisture loss during storage (4C) of cut apples, potatoes, carrots, and onions was investigated. Oxidative discoloration, as determined by the Commission Internationale de I'Eclairage L*a*b* color scale, was significantly reduced (P < 0.05) by treatments over a storage time of 120 min. Loss of lightness was reduced by CC, SPI and SWP coatings. These respectively showed 2.7, 3.3 and 1.5% change of L* value in coated apples as compared with 7.4% in the control. Browning in cut potatoes was significantly reduced from a 145.1% increase in the a* value of the control to 45.9, 37.0 and 30.3% increase for CC, SPI and SWP treatments, respectively. The b* values also reflected the effectiveness of SWP. The moisture barrier effect, tested over a period of 5 days at 4C, was significantly better for the treatments than control. SWP was the best and significantly reduced moisture loss in potatoes and carrots by 40 and 59%, respectively, over control. Cut onions did not show any treatment effect both in terms of off‐color development and moisture loss. The reasons for the excellent moisture barrier and antioxidative property of SWP were discussed.

PRACTICAL APPLICATIONS

Oxidative degradation of fresh fruits and vegetables is a major problem faced by the industry today. Most of the fresh produce is grown in the southwestern part of the country, requiring days of transportation to retail outlets. As the educated consumer is highly health conscious, any effort in extending the shelf life will have to be nonchemical, and preferably natural. Because of small profit margins, the intervention must also be inexpensive. Millions of MT of sour whey, a by‐product of cottage whey manufacture, is wasted because of the lack of appropriate food applications. It is natural, nutritious and presently very inexpensive. Our research investigated the possibility of using this by‐product as a final wash to enhance the so‐called window of freshness of fresh produce and fruit.

     

Effects of added phenolics on the storage stability of avocado and coconut oils

This study investigated the effects of added phenolics on the storage stability of avocado and coconut oils. Avocado and coconut oils in the absence (control oil) and presence (treated oil) of caffeic acid (CA) or p‐coumaric acid (pCA) were stored at 20 and 60 °C for 50 days. The total phenolic content, peroxide value, p‐anisidine value (p‐AV), free fatty acids (FFAs) and FA composition of the obtained oils were examined on days 0, 7, 15, 23, 35 and 50. Results showed that storage at 60 °C accelerated oil oxidation, and the CA or pCA helped preserve avocado and coconut oils to different extents. CA and pCA protected some desirable unsaturated fatty acids at 60 °C, but facilitated the hydrolysis of triglycerides. Substantially extractable phenolics were still detected in the treated oils after either storage. Incorporation of phenolics into oil products is feasible and beneficial for increasing oil stability and nutritional value.     

Effect of various additives to marinating baths on some properties of cattle meat

Longissimus dorsi (LD) muscles obtained from young bull carcasses (Holstein Friesian) were marinated, using solutions containing 0.5% sodium tripolyphosphate (STP), 0.5% dicalciumhydrogen phosphate (CHP) and 0.5% citric acid (CA). All solutions, including a blank, contained 2% NaCl. Expressible moisture, cooking loss, marinade uptake, area gain (increase in slice size), colour coordinate values (L*, a*, b*), marinade and meat pH, and the textural properties of samples were evaluated. Marinating with STP and CHP solutions resulted lower cooking losses. Marinade uptake and area gain were lower for control steaks and steaks marinated with the CA solution. The highest lightness was found in steaks marinated with the CA solution. Steaks marinated with STP and CHP solutions were darker. The CA solution resulted in yellowness of steaks. All treatments significantly affected hardness, chewiness and resilience values of steaks. The lowest hardness value was found in steaks marinated with CA. STP and CHP treatments also improved tenderness.