This paper presents the results of the research on the use of fish oil (FO) in combination with soybean oil (SO) in laying hens diet on physical and chemical properties of fresh eggs and those stored ...in a refrigerator for 28 d at + 4°C. Fatty acids (FA) profile, as well as thiobarbituric acid reactive substances (TBARS) values in yolks are also presented. The following feeding treatments have been used: C (control, without FO), E1 (0.3% FO + 4.7% SO), E2 (0.6% FO + 4.4% SO), E3 (0.9% FO + 4.1% SO), E4 (1.2% FO + 3.8% SO) and E5 (1.5% FO + 3.5% SO). Laying hens diets were balanced at the level of 176.10 g/kg crude protein and 11.50 MJ/kg ME. The results of the study showed that feeding treatments affected the relative shares of the eggs basic parts (P < 0.05). The egg storage duration significantly reduced Haugh units (HU), egg and albumen egg weight, and increased the yolk color intensity (P < 0.001). Fish oil share increment in the diets resulted in the EPA (eicosapentaenoic FA) content increase from 10.27 to 20.10 mg/100 g egg; DHA (docosahexaenoic FA) from 105.44 to 236.87 mg/100 g egg and ∑ n-3 PUFA (polyunsatureated FA) from 204.59 to 327.35 mg/100 g egg. The ∑ n-6 PUFA/∑ n-3 PUFA ratio decreased from 8.69 (C group) to 4.54 (E5 group). TBARS values were affected by feeding treatments as well as treatment-storage interactions (P < 0.01).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The research objective was to determine the influence of marigold extract and storage duration on the indicators of egg quality and on the oxidative stability of eggs. The 5-wk long research was ...carried out on 300 laying hens. Laying hens were divided into control group (C-without marigold extract supplementation) and 2 experimental groups (E1-supplemented 1 g/kg of marigold extract and E2-supplemented 2 g/kg of marigold extract to diet). The eggs were analyzed on 2 occasions, as fresh eggs (1 D after collecting in the facility) and after 28 D of storage in a refrigerator on +4°C. On both occasions, there were 30 eggs analyzed per each group. Statistical analysis of the research results proved influence of marigold extract supplementation and storage duration on the weight of eggs (P < 0.05) and on the eggshell thickness (P < 0.001), but they did not have any influence on other indicators of external egg quality. Storage duration affected (P < 0.001) all indicators of internal egg quality, whereas supplementation of marigold extract influenced (P < 0.001) only the pH value of yolk. Supplementation of marigold extract influenced (P < 0.001) the yolk color intensity. There was a significant increase in the value of yolk color, starting with 9.63 in the C group and raising to 12.77 (E1) and 13.50 (E2) in fresh eggs. Yolk color of stored eggs was more intensive than the yolk color of fresh eggs in all 3 groups (P < 0.001). Supplemented marigold extract did not influence the obtained results of lipid oxidation in yolks, whereas storage duration had influence (P < 0.05) on oxidation intensity. The most favorable value of oxidation in fresh eggs was determined in the E2 group (0.545 μg MDA/g), and in stored eggs in the E1 group (0.615 μg MDA/g). Based on the research results, it was concluded that the supplementation of marigold extract had favorable influence on the yolk color intensity and on the oxidative stability of eggs without having negative influence on other egg quality indicators.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study aimed to modify the feed mixtures of laying hens to enrich the consumer eggs with n-3 polyunsaturated fatty acids (PUFA): α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and ...docosahexaenoic acid (DHA). One hundred and twenty Tetra-SL laying hens used in the study were divided into three groups of 40 laying hens arranged in five repetitions: C, control with 5% soybean oil; E1, 0.5% fish oil + 0.5% microalgae Schizochytrium limacinum; and E2, 0.75% fish oil + 0.75% microalgae. The composition of the mixtures was balanced at the level of 17.5% raw protein and 11.81 MJ/kg metabolic energy (ME). Feed and water were provided ad libitum, and the experiment lasted for 21 days. In this study, the different physical and chemical properties of eggs, the fatty acid profile and lipid oxidation of fat in egg yolks were analyzed. The results of the study showed that the weight of the egg yolk and that of the shell depended on the feeding treatments (P=0.014 and P<0.001), and the weight of eggs and basic parts, as well as the thickness of the shell depended on the storage duration (P<0.001). The storage time affected the pH of egg yolks and albumen and the reduction in Haugh units and albumen height (P<0.001). Significant differences were observed in the content of ALA, DHA, ∑n-3 PUFA (mg/100 g) and the n-6/n-3 PUFA ratio between the C and E1/E2 egg groups (P<0.001). The results of the study indicate that it is sufficient to use a lower level of fish oil and the microalgae Schizochytrium limacinum in hens' feed to achieve a satisfactory increase in n-3 PUFA in eggs, while maintaining optimal values of egg quality and freshness indicators.
Eggs are a foodstuff of animal origin that are widely consumed by human population. Quality of eggs depends on many factors, such as laying hens’ feed composition. Modification of laying hens’ diet ...by supplementing different fat sources affects the fatty acid profile in egg yolks. This paper presents the comparison of the fatty acid profile (FA) in fresh and boiled n-3 PUFA eggs. There is the question asked if the values referring to daily consumption of specific fatty acids in fresh eggs are credible. The portion of fatty acids in omega-3 fresh eggs is the following: SFA 30.76%, MUFA 41.97%, n-6 PUFA 22.24%, n-3 PUFA 4.96%, and the n-6/n-3 PUFA ratio is 4.51. Comparison of FA profile in fresh and thermally processed n-3 PUFA eggs (boiled for 10 min. at 95 °C) shows that there are differences in the content of specific FAs, but they are not statistically significant (P>0.05), except for myristoleic fatty acid (P<0.05). Our results, as well as the results published by some other authors, justify the presentation of fatty acids profile in eggs on the basis of fresh eggs analysis results, as there are no differences in the fatty acid profile between fresh and cooked eggs.
The paper presents the results of a research in the use of flaxseed (LO) and rapeseed oil (RO) in a combination with fish oil (FO) in the feeding of laying hens and the effect on the fatty acid ...profile of egg yolks (∑n-3 PUFA and ∑n-6/∑n-3 PUFA ratio). Nutritional treatments were as follows: C1, C2 = control (5% soybean oil SO), E1 = 1.5% LO+3.5% FO, E2 = 3.5% LO+1.5% FO, E3 = 1.5% RO+3.5% FO, E4 = 3.5% RO+1.5% FO. Feed mixtures for the laying hens were balanced on the basis of a 17% crude protein and 11.5 MJ/kg ME, and the n-6/n-3 PUFA ratio in the mixtures was as follows: C1 13.64, C2 13.10, E1 2.63, E2 1.53, E3 4.84 and E4 6.21. The combination of the flaxseed oil and fish oil in the feed affected the n-6/n-3 PUFA ratio, making it narrower when compared to the combination of rapeseed oil and the fish oil. The control feed C1 and C2 contained only ALA 3.12 and 4.08%, being without the EPA and DHA fatty acids. The analysis of the fatty acid profiles in egg yolks demonstrated that the eggs contained 1.16 and 1.26% of DHA in addition to ALA, which means that, although in the small amounts, the DHA was synthesized and deposited in the eggs by the laying hens. The following proportions of n-3 PUFAs were found in the eggs of the experimental groups: E1 6.51%, E2 8.30%, E3 5.17%, and E4 3.54%. The n-6/n-3 PUFA ratio in egg yolks decreased from 9.67 and 11.85 (control groups) to 3.08 and 2.57, respectively, for the flaxseed and fish oil treatments and 4.25 and 6.95 for the rapeseed and fish oil treatment. The studies have demonstrated a more efficient deposition of the n-3 PUFAs in the yolks of the E1 and E2 groups, although the ALA was most abundantly present in the total n-3 PUFAs.
The sensory evaluation is a scientific discipline used to evoke, measure, analyze and interpret reactions to stimuli perceived through senses of sight, smell, touch, taste, and hearing. Sensory ...evaluation applies principles of experimental design and statistical analysis to the use of human senses aiming to isolate the sensory properties of foods themselves and provide important and useful information to product developers, food scientists, and managers about the sensory characteristics of food products. To achieve the scientific control of the sensory evaluation test, good laboratory practice should be applied. It includes defining the test objective and test type, selection of right assessors, ensuring right test area, handling and preparing the sample in appropriate way, paying attention to test set-up and storing the test data safe in logical order.
Regarding eggs, sensory characteristics are usually evaluated on eggs enriched with bioactive compounds. Sensory studies are often conducted either with trained (in accordance with international reference standards) or untrained panelists. Sensory evaluation of eggs after addition of different compounds is of great importance because sensory attributes such as aroma, flavor, aftertaste and overall acceptability of enriched eggs are very important to consumers.
Senzorna procjena je znanstvena disciplina koja se koristi za evociranje, mjerenje, analizu i tumačenje reakcija na podražaje koji se percipiraju kroz osjetila vida, mirisa, dodira, okusa i sluha. Senzorna procjena primjenjuje načela eksperimentalnoga oblikovanja i statističke analize za korištenje ljudskih osjetila u pokušaju izoliranja osjetilnih svojstava hrane i daje važne i korisne informacije proizvođačima, znanstvenicima koji se bave hranom te menadžerima o osjetilnim karakteristikama prehrambenih proizvoda. Da bi se postigla znanstvena kontrola senzornoga testa procjene, potrebno je primijeniti dobru laboratorijsku praksu, koja uključuje definiranje cilja i tipa ispitivanja, odabir pravih procjenitelja, osiguravanje odgovarajućega područja ispitivanja, rukovanje i pripremanje uzorka na odgovarajući način, vodeći računa o tome da je postavljanje ispitivanja i pohranjivanje podataka ispitivanja sigurno i u logičkom redoslijedu.
Kada se radi o jajima, osjetilna svojstva obično se procjenjuju na jajima obogaćenim bioaktivnim spojevima. Senzorne studije često se (u skladu s međunarodnim referentnim standardima) provode s obučenim ili neobučenim panelistima. Senzorna procjena jaja nakon dodavanja različitih spojeva od izuzetne je važnosti, jer su senzorna obilježja, kao što su aroma, okus, naknadni okus i sveukupna prihvatljivost obogaćenih jaja, vrlo važna potrošačima.
The aim of the research was to enrich eggs with n-3 polyunsaturated fatty acids by using plant oils and fish oil as dietary supplements in laying hens’ feed. The focus was put on the effect of the ...daily consumption of 100 g of egg yolk, i.e. 100 g of egg mass, on the human health. The 1
st
group of laying hens was fed a diet containing soybean and fish oil, and the 2
nd
group was given feed containing a combination of linseed, rapeseed, soybean, and fish oils. Eggs laid by the 2
nd
group contained 4.73% α-linolenic acid, 0.20% eicosapentaenoic acid and 2.37% docosahexaenoic acid (% of total fatty acids in yolk lipids,
P
< 0.001), which marks an increase of × 4.04 for α-linolenic acid, × 3.33 for eicosapentaenoic acid, and × 1.75 for docosahexaenoic acid compared to eggs laid by the 1
st
group. Total n-3 polyunsaturated fatty acids in eggs of the 2
nd
group were × 2.8 higher than in the 1
st
first group. Calculated per 100 g of eggs of the 2
nd
group, the intake for the human body corresponds to 435 mg α-linolenic acid, 18.43 mg eicosapentaenoic acid, and 218.2 mg docosahexaenoic acid.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
For the enrichment of eggs with lutein, a marigold flower extract – MFE (Tagetes erecta L.) was used. The two groups of laying hens were involved in the study – the control group (C) and the ...experimental group (E), respectively. The laying hens of the control group were fed by the lutein‐free mixture, while the laying hens’ E group consumed the mixture with the 3 g/kg of lutein. The laying hens’ feeding lasted for 31 days, after which the quality of eggs (i.e., the shape index, egg weight and the egg main parts, shell strength and thickness, Haugh units – HU, egg white height, egg yolk color, egg white pH, and the egg yolk pH), as well as the lutein content and Thiobarbituric Acid Reactive Substances (TBARS) values in egg yolks, were determined. The study results have demonstrated that the added MFE exerted an effect of thickness, weight, and eggshell proportion reduction (P<0.001), as well as of the shell strength reduction (P=0.014). It has also reduced the HU value (P=0.039) and has increased the egg white content, egg yolk color, and the egg yolks’ lutein content (P<0.001). A statistically significant difference in TBARS values was found between the fresh and the stored eggs in group C, as well as between the C and E groups in the fresh eggs (P<0.05). Our results indicate that MFE is suitable for the enrichment of table eggs with lutein.
U svrhu obogaćivanja jaja luteinom, upotrijebljen je Marigold Flower Extract – MFE (ekstrakt cvijeta kadife – Tagetes erecta L.). U istraživanju su korištene dvije skupine nesilica – kontrolna (C) i pokusna (E). Kontrolna skupina nesilica hranjena je smjesom bez dodatka luteina, dok su nesilice E skupine konzumirale smjesu s 3 g/kg luteina. Hranidba nesilica trajala je 31 dan, nakon čega je obavljena analiza kvalitete jaja (indeks oblika, masa jaja i osnovnih dijelova u jajetu, čvrstoća i debljina ljuske, Haugh jedinice – HU, visina bjelanjka, boja žumanjka, pH bjelanjka i pH žumanjka), te je utvrđen sadržaj luteina i TBARS (Thiobarbituric Acid Reactive Substances) vrijednosti u žumanjcima. Rezultati istraživanja pokazali su da dodani MFE utječe na smanjenje debljine, težine i udjela ljuske (P<0,001), odnosno na smanjenje čvrstoće ljuske (P=0,014). Također, on utječe na smanjenje vrijednosti HU (P=0,039), a povećava udjele bjelanjka, boju žumanjka i sadržaj luteina u žumanjcima jaja (P<0,001). Statistički značajna razlika u vrijednostima TBARS-a utvrđena je između svježih i čuvanih jaja kod C skupine, kao i između C i E skupina kod svježih jaja (P<0,05). Naši rezultati ukazuju da je MFE pogodan za obogaćivanje konzumnih jaja luteinom.
U radu se istražuju fizikalno-kemijski pokazatelji kakvoće konzumnih jaja na našem tržištu. Istraživanje je provedeno na jajima dvaju različitih proizvođača, „A“ i B“, i to 7. i 28. dana skladištenja ...jaja. Prema Pravilniku o kakvoći jaja (NN 115/06. čl. 9.), jaja se klasiraju na jaja „A“ klase“ ili svježa jaja i jaja „B“ klase, namijenjena industrijskoj preradi. S obzirom na težinu, jaja „A“ klase razvrstavaju se u četiri razreda: „XL“, „L“, „M“ i „S“. Naše istraživanje odnosi se na jaja „M“ težinskoga razreda, jer se taj razred jaja najviše koristi u našim uvjetima. Od pokazatelja vanjske kvalitete jaja analizirani su indeks oblika (%), težina jaja (g), težina ljuske (g), čvrstoća (kg/cm2) i debljina (mm) ljuske, a od unutrašnjih pokazatelja težina bjelanjka i žumanjka (g), boja žumanjka, Haugh jedinice (HJ), visina bjelanjka (mm), pH bjelanjka i pH žumanjka. Rezultati naših istraživanja dopuštaju sljedeće zaključke: temeljem procjene energetske i proteinske vrijednosti, jaja proizvođača „B“ odlikuju se boljom nutritivnom vrijednošću od jaja proizvođača „A“. Rezultati istraživanja kvalitete jaja 7. dana skladištenja pokazali su da postoji statistički značajna razlika (P<0,001) između proizvođača jaja „A“ i „B“ u težini jaja, indeksu oblika, debljini ljuske, težini i čvrstoći ljuske, kao i težini bjelanjka. Nakon 28. dana skladištenja, utvrđena je statistički značajna razlika (P<0,001) u visini bjelanjka, HJ, pH vrijednostima bjelanjka i žumanjka te boji žumanjka (P=0,003). Temeljem analize nutritivne vrijednosti i fizikalno-kemijskih svojstava jaja tijekom skladištenja, jaja proizvođača „B“ odlikuju se boljom kvalitetom od jaja proizvođača „A“. Jaja obaju proizvođača zadovoljavaju uvjete propisane hrvatskim pravilnikom o kakvoći jaja.
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