فصلنامه پژوهش و نوآوری در علوم و صنایع غذایی
سال دهم شماره 3 (پاییز 1400)

In this study, nanofibers of basil seed gum (BSG) were prepared by electrospinning method. To reduce repelling interaction and helping the process of electrospinning, aiding agents such as polyvinyl alcohol (PVA) can be used. PVA (10% w/v) and BSG (1% w/v) with different volume ratios of 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20 and 90:10 were prepared. According to the SEM images, it was found that a volume ratio of 70:30 from PVA/BSG solution produced the best nanofibers to trap lycopene. The Encapsulation efficiency was in the range of 80.04-91.67%. The effect of lycopene concentration (0.4, 0.6 and 0.8% w/w) on the encapsulation efficiency was investigated. The results showed that the effect of lycopene concentration on encapsulation efficiency was statistically significant (P<0.05). The physical and chemical properties of the BSG/PVA nanofiber containing lycopene were studied with DSC test. The results of the DSC test showed that lycopene lost its crystalline structure and was present in the nanofiber mainly in amorphous form and produced a homogeneous composition. The FTIR analysis showed that there was only physical interaction between the components and no chemical interaction occurred. Generally, the results showed that the system used (BSG/PVA nanofiber) has a high potential for utilization as an appropriate delivery system for increasing bioaccessibility in bioactive compounds.

Due to the high nutritional value of vitamin D3 and its instability in various environmental and processing conditions, the need to preserve it through techniques such as capsulation during nutrification is felt. In this study, vitamin D3 was encapsulated in the structure of niosomes based on various surfactants (Span 60, Tween 20, and 80) and cholesterol with ratios (80:20 and 60:40 w/w) using by thin layer hydration-sonication method. It was found that the niosomes prepared with tween 20 and 80 with a surfactant to cholesterol ratio (80:20 w/w) had the lowest mean particle size distribution, lowest polydispersity index, and the highest zeta potential magnitude. Also, these samples had high encapsulation efficiency and their sizes were in the nanoscale. The stability of vitamin D3 was determined during 1 month at refrigerator condition for nanoniosomes samples based on tween 20 and 80 with a surfactant to cholesterol ratio (80:20 w/w). The results showed that tween 20 based nanoniosomes were more stable than tween 80 based samples during 1 month storage. Also, the bioaccessibility of vitamin D3 after complete digestion was evaluated under simulated gastrointestinal conditions. Based on this, it was found that the bioaccessibility of vitamin D3 in the free form is 58%, which the design of nanoniosomes based on tween significantly improved its bioaccessibility (P<0.05). The highest bioaccessibility of vitamin D3 was obtained for tween 20 nanoniosomes at ratio 80:20 of surfactant to cholesterol.

Spirulina platensis is a planktonic, photosynthetic filamentous cyanobacterium with bioactive molecules, which is a rich source of pigments such as phycocyanin.In this study, effects of two important factors of agitation and aeration on biomass production of S. platensis and its production of chlorophyll, phycocyanin, allofycocyanin and carotenoids at 28 °C, pH 9 and with agitation rates of 20 and 50 rpm with and without aeration were studied in immersion culture using stirring reactor. Results showed that aeration in treatments with agitation rates of 20 rpm significantly increased concentrations of the pigments (phycocyanin, allofycocyanin, chlorophyll and carotenoids) and biomass. In contrast, aeration in treatments with agitation rates of 50 rpm inhibited pigment production (P<0.05). The highest quantity of biomass and concentrations of phycocyanin, allofycocyanin, chlorophyll and carotenoids respectively were 1.39 g.l-1 and 136.5, 38, 8.62 and 3.05 mg.l-1, which were linked to treatment with aerationat 20 rpm. Based on the current results, aeration of the culture media significantly increased concentrations of allofycocyanin. Under conditions without aeration, increases in agitation rates increased biomass quantities. The highest quantity of biomass and concentrations of phycocyanin, allofycocyanin, chlorophyll and carotenoids were achieved using aeration at an agitation speed of 20 rpm.

Yogurt is one of the most popular and widely consumed dairy products that it is very important in people's food basket. Thus, the modification and improvement of its technological and nutritional properties has a special place. Aiming to improve nutritional value, syneresis reduction and reach to maximum overall palatability, the set-type yogurt was produced by adding various amount of freeze-dried orange seed protein concentrate at 0, 1, 2 and 3% and physicochemical properties (pH, acidity, syneresis and apparent viscosity) were evaluated at storage days of 1, 7, 14 and 21 at 4 °C. While the apparent viscosity and syneresis of set-type yogurt with no orange seed protein concentrate (control sample) were significantly (P<0.05) increased in the vicinity of 2.8 and 5.5 times during 21 days storage respectively, the noted parameters increased at rates of 5.7 and 4.24 times respectively in yogurt containing 3% of orange seed protein concentrate at the same conditions. While the control sample obtained only 75.5% of its maximum sensory and organoleptic (flavor, aroma, color, and creamy texture) scores, the produced yogurt comprising 3% of orange seed protein concentrate gained up to 93.5% of these attributes that corresponded to52.84% climb in total protein.

After harvesting of Sepestan (Cordia myxa) fruit, it immediately undergoes the physical and chemical spoilage. Therefore, Sepestan fruit has a limited shelf life and some procedures should be considered so that it could be stored and consumed for a longer period of time. One of the practical methods to enhance shelf life of the fruits and vegetables is their conversion into various products such as pickles. In this study, the effect of ripening extent with three different ripening degrees: unripe/green fruit, semi-ripe and ripe were evaluated on the quality of Sepestan pickles during 90 days of storage at the ambient temperature. For pickle preparation, an identical amount of 6% vinegar solution (about 25% of fruit weight) was used and physicochemical, textural, microbial, and sensorial properties of samples were evaluated during the storage period. The results showed that during the storage period, amounts of pH, hardness, cohesiveness, and all the sensory attributes of all the pickle samples decreased while acidity, adhesiveness, and the counts of lactic acid bacteria and molds and yeasts increased. Furthermore, the lowest number of lactic acid bacteria and molds and yeasts count at the end of the keeping period was related to the unripe sample and the highest amount was related to the ripe sample. Throughout the storage period, particularly at the end of 90 days, pickle sample prepared from unripe fruit had significantly (P<0.01) the highest acceptance. According to the findings of the present study, the unripe Sepestan fruit can be well used for pickle production.

Phycocyanin is a pigment extracted from Spirulina platensis and can be a good alternative to synthetic dyes in various industries, including the food industry. The aim of this study was to stabilize phycocyanin and evaluate the method in pigment stability under different pH conditions. Phycocyanin (500 ppm) in solutions at three pH (3, 5, and 7) with different ratios (0, 75, 150, 225, and 300 ppm) of rosemarinic acid, tannic acid, digallic acid was mixed as a copolymer. These solutions were placed in cylindrical containers of the same size against a light source with an intensity of 7000 lux at ambient temperature. The color changes of the solutions were examined over 14 days. The structure of the microcapsules was examined using a scanning electron microscope. The average particle diameter size and zeta potential measurement of microcapsules were determined using a special particle measuring device. The results of pigment stability study showed that the use of tannic acid as a copigmenting compound has a higher resistance effect on phycocyanin and the concentration of 300 ppm has the highest resistance. The comparison of SEM showed that microcapsules containing maltodextrin were spherical with a smoother surface and had fewer wrinkles than those made with Arabic gum. The most stable pigment treatment is related to maltodextrin coating in the ratio of acid to pigment at pH=7 and the lowest pigment stability in the ratio of 0.4 times acid to pigment at pH=3. The particle size of microcapsules with different ratios in wall compositions varies between 159.2969 to 6006.637 nm. Also, the scattering index in the microcapsule varies between 0.299547 to 3.252826, which indicates the high dispersion of particles and the heterogeneity of particle size.

Yogurt is one of the widespread dairy products, which is especially important in people's diets due to its high nutritional value and health-promoting effect. In this study, the physicochemical, quality, sensory, and microbial characteristics of yogurt containing sesame oil (1, 2, and 3%) after homogenization at two pressures of 100 and 200 bar, for 21 days storage was investigated. The samples with sesame oil had higher pH and this value increased with increasing homogenization pressure. During storage, acidity of all yogurt samples increased. Moreover, peroxide value of yogurt increased and this value was higher in sesame oil samples. Syneresis was higher in yogurts with sesame oil, but this value decreased with increasing oil especially in yogurt containing milk fat. Power law was fitted appropriately by experimental data of rheological properties. Sesame oil addition resulted in no significant effect in hardness value of samples in comparison with milk fat. The lightness of yogurts showed that only the sample contained 3% sesame oil and treated at 100 bar pressures had significant difference with other samples (P<0.05). Microbial characteristics of samples were in accordance with institute of standards of Iran. Although, sensory evaluation of samples showed that yogurt containing sesame oil had better texture than yogurt containing milk fat; however, taste and mouthfeel of them showed lower scores. Sesame oil addition caused reducing overall acceptability of yogurts that may be related to the applying of oil without deodorization.

One of the important challenges about using of the betalains is their low stability against light and heat. Therefore, the main goal of this research was to stabilize the extracted betalain from red beet against thermal treatments. To investigate the thermal stability of the betalain, encapsulation (using maltodextrin, gum Arabic, gum farsi, whey protein concentrate (WPC) and alpha and beta cyclodextrins) and co-pigmentation method using pure co-pigments such as gallic acid, ferulic acid, quercetin and rutin (at different molar ratios of 2.5-100:1 co-pigment/betalain) and rosehip extract (at two molar ratios of 50:1 and 100:1 gallic acid equivalent/betalain) were applied. The results indicated that WPC was the most effective wall material which maintained the higher betalain (81.50 mg/100 g powder) during drying and, after using the microcapsules in the model drink, the highest retained betalain (48.20 %) was related to the WPC microcapsules. Alpha and beta cyclodextrins and pure phenolic co-pigments did not have any significant effect on the betalain stability. Rosehip extract at two molar ratios of 50:1 and 100:1 (gallic acid equivalent/betalain) led to increasing of the betalain retention which was also obvious during storage at accelerated temperature and light condition, even after 14 days; so that the betalain content of the sample containing rosehip extract did not decreaseduring 14 days storage.