Fatty Acid Values Research Articles

Enrichment of a fruit-based smoothie beverage with omega-3 fatty acids from microencapsulated chia seed oil.

Omega-3 fatty acids are known for their various health benefits. Chia is the richest vegetable source of omega-3 fatty acids. However, its oil is highly susceptible to oxidative deterioration and should be protected for incorporation into food matrices. This work aimed to study the incorporation of different chia oil microcapsules in a powdered beverage, analyzing the effect on the physicochemical characteristics and stability during storage. Different types of microcapsules were obtained: monolayer microcapsules using sodium caseinate and lactose as wall material, and multilayer microcapsules produced through electrostatic deposition using lecithins, chitosan, and chia mucilage as the first, second, and third layers, respectively. The results demonstrated an efficient enrichment of smoothies, with omega-3 fatty acid values ranging from 24.09% to 42.73%, while the original food matrix powder lacked this component. These powder beverages exhibited low moisture content (≤ 2.91%) and low water activity (≤ 0.39). The aerated, packed density and compressibility assays indicated that adding microcapsules made the powders less dense and compressible. The color of the original powdered beverage was not modified. The dispersibility reflected an acceptable instantaneity, reaching the maximum obscuration after 30 s of stirring. The solubility of all the enriched products was higher than 70%, whereas the pH was ~6.8. The contact angle between the powder and liquidindicated an excellent ability to be reconstituted in water. The analysis of the glass transition temperature showed that the storage temperature (25 °C) was adequate. The peroxide value of all the products was low throughout the storage (≤ 1.63 meq peroxide kg-1 of oil at 90 days at 25 ± 2 °C), thus maintaining the quality of the microencapsulated chia oil. The results suggest that incorporating the monolayer and multilayer chia oil microcapsules that were studied could be a viable strategy for enriching smoothies with the omega-3 fatty acids present in chia seed oil. © 2023 Society of Chemical Industry.

Changes in quality characteristics and metabolites composition of wheat under different storage temperatures

The quality variation of wheat post harvesting is strongly affected by storage temperature. Low temperature storage can alleviate the quality deterioration in wheat after harvest. However, the mechanism regarding metabonomics analysis between different storage temperatures in postharvest wheat remains poorly understood. Here, we analyzed the changes in wet gluten content, fatty acid values, Catalase (CAT) activity, alpha-amylase activity, pasting properties changes, as well as the differentially expressed key metabolites in wheat, stored at 15, 20, and 30 °C for 180 days. In our study, wheat storage, processing, and edible quality remained steady at 15 °C and 20 °C storage temperatures, and wheat quality drastically degraded at 30 °C. Through non-targeted metabolomics analysis, carbohydrate metabolism, fatty acid metabolism, amino acid metabolism, and nucleotide metabolism pathways were proven to be involved in wheat storage. Specifically, gamma-glu-cys and 4-trimethylammoniobutanoic acid were up-regulated; adenine, l-gluconic acid, linoleic acid, 13(s)-HPODE, 9(s)-HPODE, 9-OxoODE, n-acetyl-l-glutamic acid, and trans-2,3-dihydroxycinnamate were down-regulated at 15 °C and 20 °C. These substances helped maintain the stability of cellular structures within the wheat kernel. The study's findings revealed the low-temperature impact mechanism on high moisture wheat from the perspective of metabolite changes. This may provide a scientific basis for the efficient preservation of wheat.

Characterization and antioxidant potential of white mustard (Brassica hirta) leaf extract and stabilization of sunflower oil

Abstract The current study aimed to analyze the stabilization of sunflower oil using white mustard (Brassica hirta) leaf extracts as well as their antioxidant potential and cytotoxicity. Selected plant leaves were macerated in different solvents such as n-hexane, chloroform, ethyl acetate, n-butanol, and methanol. The total flavonoid contents, total phenolic contents, the antioxidant activity by DPPH assay, and the inhibition of linoleic acid oxidation were also examined. Moreover, the stabilization of sunflower oil was evaluated by calculating the conjugated dienes, conjugated trienes, peroxide value, p-ansidine, and free fatty acid values. The cytotoxicity study in terms of the hemolytic activity of B. hirta leaf extract was evaluated and the maximum percentage of lysis was found to be safe (less than 5%). The results of the present study revealed that among others, methanolic white mustard (B. hirta) leaf extract possessed higher antioxidant potential and might be safely employed for the stabilization of vegetable oils.

Effects of Viscozyme L on the Yield of Oil Obtained from Fresh Avocado Fruit Pulp (Persea americana Mill.) by Three-Phase Partitioning Extraction Method

The applicability of Viscozyme L in extraction for recovery of avocado oil from fresh fruit pulp was studied. The effects of enzyme concentration, incubation temperature and time on the yield of avocado oil extracted by enzyme-assisted three-phase partitioning (EATPP) extraction method were investigated and the physicochemical properties of the final oil were evaluated. The highest oil yield obtained by EATPP using Viscozyme L was 39.79 ± 1.02 % on the dry basis of material, significantly higher than that extracted by TPP without enzyme (18.5 ± 0.76 %). The best conditions were 1.5 % (v/w) enzyme concentration, incubation at 50 °C for 1 h. Meanwhile, the yield of oil extracted by Soxhlet method was 58.10 ± 0.65 %, obviously higher than EATPP.  However, EATPP gave better oil in terms of quality. The free fatty acid value of oil extracted by EATPP (0.87 ± 0.08 %) showed no significant difference compared to the oil extracted by Soxhlet method. Besides, oil extracted by EATPP had lower peroxide value (6.75 ± 0.29 meq O2/kg oil) and higher total phenolic content (63.60 ± 2.73 mg GAE/100 g oil) than that by Soxhlet method. The fatty acid compositions of the oil extracted by EATPP mainly consist of palmitic acid, palmitoleic acid, oleic acid, and linoleic acid. The extraction of oil from fresh avocado fruit pulp utilizing EATPP can be used as an efficient method to reduce the avocado loss, thus saving cost, and increasing the product varieties from this kind of fruit.

Optimization of ohmic parameters in enzyme assisted aqueous extraction for better physico-chemical properties of the black cumin seed oil

This study was carried out to optimize the ohmic heating parameters for enhancing physico-chemical properties of oil from enzymatic hydrolyzed black cumin seed. The effect of electric field strength (EFS) including 550, 650,750,850 and 950 V/m, the end point temperatures (EPT) 50, 60, 70, 80 and 90 ºC, holding time (HT) 0, 5, 10,15 and 20 min and pH levels 2, 3, 4, 5 and 6 were optimized for the extraction process. The response in terms of oil yield, refractive index, specific gravity, color, free fatty acids, saponification, and peroxide values of the extracted oil was studied. Statistical analysis and optimization of process parameters were performed using the response surface methodology. The results revealed that 56.54–64.18% of oil yield was obtained in enzymatic aqueous extraction and in combination with ohmic heating, was increased from 64.18% to 85.71%. From the numerical optimization it is observed that, EFS of 718.22 (V/m), EPT of 66.08 (°C), HT of 14.07 (min) and pH of 3.7 facilitates the oil yield, specific gravity, color, free fatty acid, saponification, and peroxide values were 79.12%, 0.798, 46.68, 0.672%, 181.42 mg KOH/g and 1.128 meq O2/kg, respectively. It is confirmed that there is not statistically significant (P < 0.05) difference was observed between the predicted and actual values. Thus, it could be concluded that the optimum conditions of ohmic heating parameters could be enhanced by oil yield and maintaining the natural of physico-chemical properties of enzymatically hydrolyzed black cumin seed oil.

Determination of bioactive properties of Capparis spinosa fruits and use in production of Tulum cheese

The focus of the present study was to evaluate the bioactive properties of Capparis spinosa (caper) fruits and to investigate some quality parameters of Tulum cheese with addition of caper. Analyses for the phytochemical components of caper fruit used in the production of Tulum cheese showed that it has high levels of bioactive components in terms of antioxidant activity, total phenolics, and flavonoids. It was determined that C. spinosa, which is used in the production of Tulum cheese, had a good radical scavenging activity (DPPH radical assay). Four experimental groups were arranged in the present study and analyzed on the 1, 30, 45, 60, and 90th day of ripening. T_C was designed as the control group, T_C1, T_C2, and T_C4 groups contained 1, 2, and 4% of caper. According to the obtained results as the content of caper increased, dry matter ratios, ash, pH values, tyrosine and free fatty acid values in cheese increased significantly. The microbiological evaluation revealed that the caper affected positively Lactobacillus spp. counts. The highest aroma and taste scores among caper cheeses were given to the control group (T_C). Generally, caper did not have a negative effect on the textural profile of the product. These results revealed that C. spinosa contributes to the improvement of the bioactive potential as well as increasing the quality parameters of cheese.&#x0D; Keywords: Caper; Bioactive properties; Functional dairy; Microbiological properties; Tulum cheese

Investigation of volatiles and quality attributes of indica-japonica hybrid paddy by radio frequency combined hot air drying

The study was aimed at investigating the effects of radiofrequency combined hot air drying (RF-HAD) on volatiles and quality attributes of indica-japonica hybrid paddy. The results indicated that RF-HAD reduced the drying time by 40% compared to hot air drying (HAD). In addition, HA-RF-dried samples showed significantly higher color, vigor, and taste value but less fatty acid value than HA dried-ones. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that RF-HAD did not affect the protein profile of rice protein. Gas chromatography-ion mobility spectrometry characterized changes in volatile components of paddy before and after drying, results showed that the content of aldehyde and ester aromatic compounds increased after drying and the content of most volatile components in RF-HA-dried paddy was higher than in HA-dried samples. Thus, the inference was that RF-HAD technology may be an innovative alternative to existing drying methods such as microwave, HA, and other drying technologies.

Fatty acid profiling and oxidative stability of biscuits available in the market of the city of Ludhiana, India

India has occupied third position in biscuit manufacturing with an average production of 1.95 million tonnes. The major ingredients in biscuit manufacturing are refined wheat flour, sugar and fat. Fat to be used must be chosen carefully as it affects quality of final product in terms of fatty acid composition and oxidative stability. Therefore, the present work was planned to study fatty acid profile of highly consumed baked products of biscuit family such as biscuits and cookies available in market. The study was carried out to do fatty acid profiling of a range of highly consumed baked products of biscuit family as a primary objective and also, to determine oxidative stability of these products by analysing peroxide value and free fatty acid content. The most commonly consumed packaged and unpackaged bakery products were selected and were bought from the local market of Ludhiana city on the basis of a survey conducted on 200 subjects. The selected products were analysed for fatty acid composition and oxidative stability using standard methods. Fatty acid profiling of 22 bakery products of biscuit family was done. Palmitic acid was the most abundant among all fatty acids in packaged and unpackaged samples. Peroxide value of all the products even after storage period of three months was found below the permissible limits (< 10 meq/kg). Free fatty acids value of all the products also did not cross acceptable level of 0.5 percent. Out of total selected eight brands, six were national and two were international. Amount of palmitic acid was higher in the products belonging to local brands.

The stable carbon and hydrogen isotopic composition of microbial fatty acids traces microbial metabolism in soils and peats

The compound-specific stable carbon (δ13C) and hydrogen (δ2H) isotopic compositions of microbial fatty acids have been widely used to trace microbial metabolism across a range of mesophilic environments. However, few studies have combined the δ13C and δ2H values of microbial fatty acids. So far none have determined the δ2H of microbial phospholipid fatty acids (PLFAs) in soils or peats, even though these stable isotope combinations could provide new insights into soil microbial metabolism. Here, we measured the δ13C and δ2H values of microbial PLFAs in top soils from peatlands, meadows, and woodlands in the Dajiuhu basin, central China. We observed a significant (p < 0.05) positive correlation between the δ13C and δ2H of microbial PLFAs across the three habitats studied here, indicating that central metabolic pathways affect both carbon and hydrogen isotopic compositions of microbial PLFAs. Moreover, our stable isotope data consistently indicate a relatively conservative metabolic state, which is dominated by expected heterotrophic metabolism. The exception to these observations is PLFAs associated with methanotrophs, as these appear to have decoupled carbon and hydrogen isotopes, providing an additional tool for tracing methanotrophic signals. Our results suggest that the carbon and hydrogen dual isotopic composition of microbial PLFAs can not only provide cross-validation for microbial metabolism in natural environments, but as a combined tool can also provide new insights into the perturbation of soil microbial community metabolism.

Involvements of membrane lipid and phenolic metabolism in reducing browning and chilling injury of cold-stored Chinese olive by γ-aminobutyric acid treatment

The influences of 1.0 mM γ-aminobutyric acid (GABA) treatment on browning, chilling injury (CI), membrane lipid metabolism, and phenolics metabolism in 2 °C-stored Chinese olive were explored. In comparison with the control Chinese olive, GABA-treated Chinese olive manifested lower CI index, browning index, browning degree, and cell membrane permeability. Additionally, GABA-treated Chinese olive exhibited lower values of saturated fatty acids (SFAs) and phosphatidic acid, lower activities of lipoxygenase, lipase, and phospholipase D, but higher levels of unsaturated fatty acids (USFAs), phosphatidylinositol, and phosphatidylcholine. Moreover, GABA-treated Chinese olive displayed lower PPO and POD activities, but higher activity of PAL, higher values of flavonoids and total phenolics. These data indicate that GABA treatment contributed to alleviating browning and CI occurrences in Chinese olive during the chilling process. This effect was achieved by postponing the degradations of membrane lipid and USFAs, preventing the oxidation of phenolic substances, as well as maintaining the integrity of cellular membranes.

Effects of hot air-assisted radio frequency stabilization of brown millet and millet bran: Enzyme inactivation, microstructure, nutritional quality, and storage stability

Brown millet (BM) and millet bran (MB) are rich sources of nutrients, but their storage is affected by rapid rancidity deterioration, which primarily due to the activity of lipase (LA) and peroxidase (POD). High moisture content and water activity also have adverse effects on rancidity. In order to inactivate enzyme activities and extend storage stability of BM and MB, hot air-assisted radio frequency (HA-RF) heating was applied in this study. BM was treated at 95 °C and 105 °C while MB was heated to 105 °C and 115 °C with various holding times. The effects on enzyme inactivation, microstructure, nutritional quality, and storage stability of the samples were investigated. The results showed that HA-RF treatment effectively reduced LA and POD activities in both BM (<13%) and MB (<10%); Low-temperature (95 °C for BM and 105 °C for MB) HA-RF treatment caused less damage to the structure of the samples and maintained the structural integrity of most starch and proteins, although the treatment significantly (p < 0.05) reduced free phenolic and flavonoid contents of the samples; Low-temperature HA-RF treatment had less impacts on main nutrients of BM and MB when compared to the high-temperature treatment (105 °C for BM and 115 °C for MB). HA-RF stabilization effectively improved the storage stability, and slowed down the increase in fatty acid value (FAV) and malondialdehyde (MDA) content during storage.

Effect of Individual and Synergistic Addition of Moringa Oliveira Seeds and Leaves Powder to Broiler Diets in some Physiological and Microbial Traits and Oxidation Indicators

This study was conducted at the poultry farm\\Abu Ghraib, College of Agricultural Engineering Sciences, University of Baghdad, for the period from 12-10-2022 to 22-11-2022 for 42 days to study the effect of individual and synergistic addition of Moringa oleifera seeds and leaves powder to broiler diets on some physiological and microbial traits. 210 commercial broiler chicks (Ross-308) one day old unsexed, randomly distributed to seven treatments with three replicates 10 birds each replicate and the treatments were contained: T1 (control treatment) without additive, T2: 1% seeds powder, T3: 2% seeds powder, T4: 1% leaves powder, T5: 2% leaves powder, T6: 0.5% seeds powder + 0.5 leaves powder, T7: 1% seeds powder + 1% leaves powder. The results indicated that no significant differences appeared between all the parameters in the biochemical characteristics of blood lipids, while the addition treatments recorded a significant decrease (P≤0.05) in the value of peroxide (P.V) and in the value of malondialdehyde (MDA) and free fatty acids (FFA) in the liver compared to the control treatment. As well as a significant increase (P≤0.05) was observed for the numbers of beneficial bacteria for the T5 bird group compared to the control treatment, T5 recorded a significant decrease (P≤0.05) in the numbers of harmful bacteria compared to the control treatment. It can be concluded that adding individually and synergistically Moringa oleifera seeds and leaves powder to broiler diets improves some of the immune and microbial traits.

Use of Aqueous Extract of Matcha Tea as an Antioxidant in Poultry Meat Storage

This study aimed to evaluate the effect of aqueous extract of matcha tea on the oxidation of fats, and some traits of poultry breast meat kept in cool storage. The study included six treatments: T1 control, T2 distilled water, T3 matcha tea 0.5%, T4 macha tea 1.0%, T5 macha tea 1.5% and T6 industrial antioxidant BHA. Pieces (2 × 3 cm) of the breasts were fleshed with the aforementioned solutions and stored by refrigeration, and some physiochemical, and chemical tests were conducted every 3 days. The results of GC-MS examination of the aqueous extract of matcha tea showed the presence of some active compounds in large amounts, and caffeine represented 81.78% of them. The results of pH values and water holding capacity showed a significant decrease (P ≤ 0.05) in submerged breast meat cuttings in aqueous extract of matcha tea at concentrations (0.5, 1.0, 1.5%) with a clear superiority for treatment T4 (1%) in the pH values and water holding capacity, as compared with the control sample. Treatments with aqueous extract of macha tea (T3, T4, T5) showed significant decreases (P ≤ 0.05) in the oxidation indicators, and a superiority in TBA and peroxide values were observed for treatment T4 upon all treatments except the industrial antioxidant (T6), as well as the values of free fatty acids which were decreased. Values of volatile nitrogen in the cold stored chicken breast meat showed that the values of T4 treatment were the closest to the results of the industrial antioxidant treatment.

Comparison of Fatty Acid Profile and Quality Properties of Commercial Apricot (Prunus Armeniaca) Kernel Oils

Prunus armeniaca L. known as apricot, is one of the important export products of Turkey and its kernel oil has become widely popular in different fields such as food pharmacy, aromatherapy and cosmetics industry. Apricot oil obtained from the kernels of apricots is characterized by high contents of oil, fiber, various minerals, proteins, vitamins and phenolics with health-improving effects. The aim of this study was to compare the fatty acid composition and some quality properties of 10 different kinds of apricot kernel oils produced by the different brands. The lowest value of free fatty acid with 0.30 % was determined in the A5 sample. The antioxidant activity results of A1 brand apricot oil sample were found similar to A4 brand apricot oil (P&gt;0.05). In the results of the total phenolic content was lowest in A5 sample with 101.17 mg GAE/100g. The results of the highest antioxidant activity and total phenolic content were determined in the sample A3. The common major fatty acids in the analyzed oil samples were determined as oleic acid, linoleic acid, palmitic acid and stearic acid. Oleic acid was determined as the main unsaturated fatty acid component for all oil types except the A1 sample.

Effectiveness of Zinc Oxide Nanoparticles and Artemisia herba alba Extract on the Chemical Composition of Soft Cheese

This study was conducted to assess the impact of ZnONPs and Artemisia herba alba extract loaded on manufacture edible gelatin in the chemical composition of cheese during the various storage periods and five transactions of cheese were manufactured which included the (T1) control sample, (T2) membrane of gelatin without adding, membrane of gelatin with loaded of ZnONPs (T3), membrane of gelatin with loaded Artemisia herba alba extract (T4) and (T5) was added ZnONPs and Artemisia herba alba extract on edible gelatin. The results of the cheese storage showed that the humidity rate had decreased morally ( p < 0.05) up to the end of the storage period and the transaction (T1) was more moisture loss to record (53.34), also found that protein, fat and ash ratios did not show moral differences at the time of one day compared with the control sample (T1) These ratios then gradually increased as long as conservation lasted and reached its highest values at 21 days. pH values have decreased morally to be at the end of the storage period between (6.10-6.26) compared with the control sample which was (5.78) and found that the fatty acid values of all transactions were morally low compared to the control sample (T1) At the time of one day, the ratio of free fatty acids rose and reached its highest values among (0.57-0.40)% for all treatments compared to the (T1) control treatment at the end of the storage period which reached (0.65%).

Influence of storage on physico-chemical physiognomies of fermented whey cereal (pearl millet and moth bean) beverage.

The present study concludes the impact of storage on changes in physico-chemical characteristics of fermented whey cereal (pearl millet and moth bean) beverage. The beverage was prepared by fermented whey (standardised to 4% fat and 18% total solids) supplemented with germinated pearl millet and moth bean slurry & using NCDC-167 as starter culture for 6-8h at 37°C. The developed beverage was then stored at 5°C for 4weeks. The samples were analysed for physico-chemical characteristics (pH, titrable acidity, viscosity, tyrosine, FFA, wheying off), sensory qualities changes and microbial quality changes (standard plate count, lactic acid bacteria count, coli form counts) at 3days' interval for 4weeks at 4°C. Control was prepared standardised whey (4% fat and 18% total solids) while treatments were prepared using standardised milk. During storage: acidity, tyrosine values, free fatty acid values and wheying off increased in all the samples The upsurge was on higher side in non nisin treated and non thermised samples compared to control formulation. However, all the samples remained sensorily acceptable upto 12th day of storage. Basic and thermised as well as nisin treated fermented whey cereal products epitomize innovative dairy products with desired functional characteristics with decent shelf life.

Untargeted Lipidomics Reveal Quality Changes in High-Moisture Japonica Brown Rice at Different Storage Temperatures.

Low temperatures are an effective way of delaying grain rancidity and deterioration. However, little is known about the difference in quality changes in high-moisture japonica brown rice at different storage temperatures. In this study, the storage quality changes in japonica brown rice with a 15.50% moisture content stored at 15 °C, 20 °C, and 25 °C were investigated. In addition, an untargeted lipidomics analysis coupled with gas chromatography and mass spectrometry (GC-MS) was applied to analyze the volatile compounds and metabolite changes in the high-moisture japonica brown rice. The results showed that storage at 15 °C could well maintain the color and aroma stability of the brown rice and delay the increase in fatty acid value (FAV). The lipidomics results showed that storage at 15 °C delayed glycerolipid and sphingolipid metabolism and reduced glycerophospholipid catabolism in the brown rice. The low-temperature environment regulated these three metabolic pathways to maintain higher contents of triglycerides (TG), phosphatidylserine (PS), abd phosphatidylethanolamine (PE), and lower contents of diglycerides (DG), OAcyl-(gamma-hydroxy) FA (OAHFA), ceramides (Cer), and glycosylceramides (Hex1Cer) in the high-moisture japonica brown rice, which maintained the storage stability of the brown rice. Our results proposed the cryoprotection mechanism of postharvest brown rice from the perspective of volatile compounds and metabolite changes, providing a foothold for the further exploration of low-temperature storage as a safe and efficient cryoprotectant in the grain storage field.

Biodiesel production from waste cat fish oil using heterogeneous catalyst from cat fish born: A viable waste management approach, and ANN modeling of biodiesel yield

Biodiesel from vegetable or animal feedstock can serve as a suitable source for renewable energy. This study utilized heterogeneous catalyst obtained from fish bone for biodiesel production from raw cat fish waste (CFW) oil. The CFW oil yield obtained using wet reduction extraction method was 96.85 %. The heterogeneous catalyst was prepared by calcination at 600 °C, for 4 h and characterized using SEM-EDX. Catalyst characterization showed suitable elements that can improve the catalytic activity. Physiochemical characterization results showed that viscosity of CFW oil (48.782 mm2/s), reduced to 9.391 mm2/s in the produced biodiesel. Similarly, after transesterification free fatty acid (3.593 mg/KOH/Kg) and acid value (7.186 mg/KOH/Kg) of CFW oil reduced to 1.48 mg/KOH/Kg and 2.96 mg/KOH/Kg, respectively, in the biodiesel. Finding from the Fourier Transform Infrared (FTIR) Spectrum of the raw CFW oil showed the presence of –OH and was assigned to the axial deformation of water molecule. However, the –OH group disappeared in the FTIR spectrum of biodiesel due to the transesterification process. This observation is consistent with the findings for moisture contents of raw CFW oil (0.073 %) and biodiesel (0.00 %), which showed disappearance of water after transesterification. The biodiesel yield was further modeled using three algorithms (Scaled conjugate gradient, Bayesian regularization and Levenberg maraquardt) of the artificial neural network (ANN). It was evident that the predictions from the Scaled conjugate gradient algorithm were comparable to the experimental responses. Finally, transesterification of raw CFW oil using heterogeneous catalyst from fish bone, was a cost-effective approach for biodiesel production.

Effects of Supplementary Kelp Feeding on the Growth, Gonad Yield, and Nutritional and Organoleptic Quality of Subadult Sea Urchin (Strongylocentrotus intermedius) with Soya Lecithin Intake History.

A 23-week feeding experiment was conducted to investigate the effects of supplementary kelp feeding on the growth, gonad development, and nutritional and sensory properties of sea urchin (Strongylocentrotus intermedius) with soya lecithin (SL) intake history. The feeding experiment was divided into experimental phase I and phase II. During phase I, 48 subadult sea urchins (initial weight: 6.28 ± 0.07 g) were fed one of the feeds with different levels of SL (0%, 1.6%, 3.2%) or kelp (Saccharina japonica) for 12 weeks. Then, all sea urchins were fed kelp for the next 11 weeks during the phase II. Each diet was randomly allocated to six cages of sea urchins. The results of phase I showed that weight gain rate (WGR), gonadosomatic index (GSI), gonad sensory properties (color and texture), and essential amino acid (EAA) contents were not significantly affected by SL level in the feed groups. High level (3.2%) of SL suppressed gonad development of S. intermedius with retarded gametogenesis in the 3.2% SL group (stage Ⅱ) compared to those fed 0% and 1.6% SL groups (stage Ⅲ). Sea urchins fed dry feeds exhibited significantly lower WGR and values of color (redness and yellowness) and texture (hardness and gumminess) but higher contents of EAA in the gonads than those fed kelp. The n-3/n-6 polyunsaturated fatty acid (PUFA) and eicosapentaenoic acid (EPA) of gonads in the groups fed with dry feeds showed no significant differences, but were significantly lower than that of kelp group. At the end of phase II, the gonad yellowness and EPA content of gonads in all dry feed groups were significantly increased by supplementary kelp feeding, with a higher increase observed in S. intermedius with SL intake history, while arachidonic acid (ARA) content was significantly improved by supplementary kelp feeding in S. intermedius with SL intake history. Gonad texture was improved to some extent by supplementary kelp feeding. These results indicated that S. intermedius fed dry feeds showed significantly higher GSI and EAA but poorer organoleptic quality and lower n-3/n-6 PUFA and EPA than those fed kelp. Kelp supplementary feeding improved the fatty acid value and organoleptic quality of gonads, especially for the sea urchins with SL intake history.

The mechanisms of pH regulation on promoting volatile fatty acids production from kitchen waste

The anaerobic acid production experiments were conducted with the pretreated kitchen waste under pH adjustment. The results showed that pH 8 was considered to be the most suitable condition for acid production, especially for the formation of acetic acid and propionic acid. The average value of total volatile fatty acid at pH 8 was 8814 mg COD/L, 1.5 times of that under blank condition. The average yield of acetic acid and propionic acid was 3302 mg COD/L and 2891 mg COD/L, respectively. The activities of key functional enzymes such as phosphotransacetylase, acetokinase, oxaloacetate transcarboxylase and succinyl-coA transferase were all enhanced. To further explore the regulatory mechanisms within the system, the distribution of microorganisms at different levels in the fermentation system was obtained by microbial sequencing, results indicating that the relative abundances of Clostridiales, Bacteroidales, Chloroflexi, Clostridium, Bacteroidetes and Propionibacteriales, which were great contributors for the hydrolysis and acidification, increased rapidly at pH 8 compared with the blank group. Besides, the proportion of genes encoding key enzymes was generally increased, which further verified the mechanism of hydrolytic acidification and acetic acid production of organic matter under pH regulation.