Thermal dependencies of fruit puree density

Density is among the key properties of liquid food media, affecting homogenisation and dispersion. The work aimed to study the temperature effect on fruit puree density, determine temperature constants and grade purees by density. The study included apple, pear and cherry plum purees. Pycnometric densities were measured at 20, 30, 40 and 50ºC temperatures. Different media were shown to vary in the density reduction rate at increasing measurement temperatures. The correlation coefficient was strongly dependent on the reference (baseline) density and extremely — on temperature coefficient. Correlation dynamics modelling of elevating temperature revealed the slope vs. temperature coefficient pairwise correlation to monotonously increase starting from very high baseline values of >0.999. The relative slope vs. baseline density pairwise correlation coefficient decreased monotonously from 0.9032. It was additionally found that the media density grading is temperature-dependent. Thus, the descending series was pear–apple–cherry plum at 0–+24.68ºC, pear–cherry plum–apple at +24.68–+84.34ºC, cherry plum–pear–apple at +84.34–+174.31ºC and cherry plum–apple–pear at ≥+174.31ºC. For three study media, the number of temperature ranges inducing puree density gradients was 4. This approach to study thermal impact on the density of food fluids is generally acknowledged and can be successfully applied in the areas, where physical density and its comparative assessment are substantive.

Dependence of surface tension of fruit puree on temperature exposure

When developing food products with new properties using innovative technologies, it is important to obtain data on the physicochemical, thermal-physical and structural-mechanical properties of the processed food media. So, one of the key components in the selection of the mode of collapsing ultrasonic cavitation is the surface tension of vegetable purees. The paper presents research data (2020) on the effect of temperature on the surface tension coefficient of fruit puree of different viscosity. The objects of research are cherry plum, pear and apple puree, combined in a row by viscosity. The surface tension coefficient was determined by the stalagmometric method, for which the puree was preliminarily centrifuged. The measurements were carried out at temperatures of 25 and 35 °С. It was found that, under equal conditions of centrifugation of puree, the proportion of supernatant in pear puree is noticeably higher – 77.37 % to the weight of puree in comparison with cherry plum puree (67.20 %) and apple puree (52.75 %). This fact can be explained by the presence of stony cells in the former which form an incompressible sediment, which allows a greater separation of the dispersed phase (sediment) and the dispersion medium (supernatant). It was found that the coefficient of surface tension of fruit purees, despite the slight difference, decreases with increasing temperature. Analysis of the steepness of the slope of the curve characterizing the effect of temperature on the surface tension coefficient showed that temperature stabilization during technological processing is more required for pear puree.

Health-related marketing messages on product labels of commercial infant and toddler food packaging in Australia: a cross-sectional audit

BackgroundProper nutrition in early childhood is essential to ensure optimal growth and development. Use of ‘better-for-you’ features on food packaging position products as healthier for children. This study aims to systematically explore the use of better-for-you labelling on infant and toddler food packaging.MethodsA cross-sectional audit of health and nutrition claims, text and images used as ‘better-for-you’ features present on infant and toddler food packaging. Data on infant and toddler food packaging were collected from five large grocery stores in Adelaide, Australia in 2019. The content of 282 unique commercial products (n=215 infant foods, n=67 toddler foods) were analysed for explicit and implicit features positioning them as better-for-you, including health and nutrition claims as well as text and images representing ‘natural.’ResultsAt least one feature of better-for-you positioning was identified on all food packaging coded. All products had characteristics coded as ‘natural’. Almost one-fifth (17%) of the products included statements in addition to mandatory allergen labelling that their products were ‘free from’ certain allergens, or gluten. One-third of the labels had statements related to enhancing development of taste, oro-motor skills and other aspects of childhood development. Of the fruit and vegetable-based infant foods displaying a sugar statement suggesting a low sugar content, 85% were sweetened with fruit puree.ConclusionsThe use of better-for-you features on infant and toddler food packaging is common and pervasive. Allergen-free and developmental claims are being used to position infant and toddler foods as better-for-you. Regulation of toddler food products separately from adult food is required, as is tighter regulation of the appropriate use of sugar and fruit puree statements on infant and toddler food packaging.

Simultaneous Detection of Seven Alternaria Toxins in Mixed Fruit Puree by Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry Coupled with a Modified QuEChERS

The presence of Alternaria toxins (ATs) in fruit purees may cause potential harm to the life and health of consumers. As time passes, ATs have become the key detection objects in this kind of food. Based on this, a novel and rapid method was established in this paper for the simultaneous detection of seven ATS (tenuazonic acid, alternariol, alternariol monomethyl ether, altenuene, tentoxin, altenusin, and altertoxin I) in mixed fruit purees using ultra-high performance liquid chromatography-tandem mass spectrometry. The sample was prepared using the modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method to complete the extraction and clean-up steps in one procedure. In this QuEChERS method, sample was extracted with water and acetonitrile (1.5% formic acid), then salted out with NaCl, separated on an ACQUITY UPLC BEH C18 with gradient elution by using acetonitrile and 0.1% formic acid aqueous as eluent, and detected by UPLC-MS/MS under positive (ESI+) and negative (ESI−) electrospray ionization and MRM models. Results showed that the seven ATs exhibited a good linearity in the concentration range of 0.5–200 ng/mL with R2 > 0.9925, and the limits of detection (LODs) of the instrument were in the range of 0.18–0.53 μg/kg. The average recoveries ranged from 79.5% to 106.7%, with the relative standard deviations (RSDs) no more than 9.78% at spiked levels of 5, 10, and 20 μg/kg for seven ATs. The established method was applied to the determination and analysis of the seven ATs in 80 mixed fruit puree samples. The results showed that ATs were detected in 31 of the 80 samples, and the content of ATs ranged from 1.32 μg/kg to 54.89 μg/kg. Moreover, the content of TeA was the highest in the detected samples (23.32–54.89 μg/kg), while the detection rate of Ten (24/31 samples) was higher than the other ATs. Furthermore, the other five ATs had similar and lower levels of contamination. The method established in this paper is accurate, rapid, simple, sensitive, repeatable, and stable, and can be used for the practical determination of seven ATs in fruit puree or other similar samples. Moreover, this method could provide theory foundation for the establishment of limit standard of ATs and provide a reference for the development of similar detection standard methods in the future.

Some Properties of Probiotic Yoghurt Produced for Babies by Adding Fruit Puree, Containing B. infantis, B. bifidum, B. longum, L. paracasei

Probiotic yoghurt with fruit was produced to enrich the intestinal flora of infants and to prevent various ailments in infants when the flora is inadequate. Peach, apple and pear purees (10% and 20% each), cow milk, milk powder, starter culture (combination of Streptococcus thermophilus, Lactobacillus delbrueckii ssp. bulgaricus, Bifidobacterium infantis, Bifidobacterium bifidum, Bifidobacterium longum and Lactobacillus paracasei) were used in the production of probiotic yogurt for babies. Some properties of yoghurt samples were investigated during fermentation and on the 1st, 7th, 14th and 21st days of storage. After ten hours of fermentation, the lowest pH was observed in samples with apple puree. It has been determined that syneresis increases with increasing concentrations of fruit purees. The water holding capacity was less in yoghurts containing fruit puree compared to control yoghurt and in 20% fruit puree compared to yoghurts containing 10% fruit puree. The number of L. bulgaricus generally increased in all samples during storage. It was determined that the number of S. thermophilus in control sample was higher than other samples during storage. The number of L. paracasei and Bifidobacterium spp. decreased during storage. While the control sample remained probiotic until the 14th day of storage, other samples lost its probiotic properties before the 7th day of storage. Considering that the number of probiotic microorganisms in a probiotic product should be at least 106-107 CFU/g according to FAO, it has been decided that the most suitable fruits for probiotic yogurt with fruit puree are peach and apple, respectively. Considering the structural features, it is more appropriate to use 10% fruit puree, and considering the probiotic feature, it is more appropriate to use 20% fruit puree. Choosing the appropriate packaging and fixing suitable storage conditions will help probiotic microorganisms to preserve their vitality for a long time.

Prospects of the microwave heating application in fruits of rowan processing

В Мичуринском государственном аграрном университете исследована возможность применения СВЧ-нагрева с целью повышения антиоксидантной ценности пюре из плодов рябины обыкновенной. В качестве стандарта при определении суммарного содержания антиоксидантов на приборе «Цвет Яуза 01-АА» выступил кверцетин. Установлено, что с увеличением температуры СВЧ-нагрева плодов рябины до 70 °С наблюдается повышение суммарного содержания антиоксидантов (ССА). Увеличение содержания антиоксидантов в свободном состоянии обусловлено происходящими в результате СВЧ-нагрева рябины изменениями клеточных структур. Установлен оптимальный режим СВЧ-нагрева плодов рябины: время - 80 сек, мощность - 700 Вт, удельная работа - 560 Вт/г·с, при котором обеспечивается максимальное увеличение ССА до 131,9 мг/100 г (507,3 мг/100 г с.в.) при содержании сухих веществ 26,2 %, что в 1,5 и 1,4 раза больше по сравнению с пюре из свежих и бланшированных плодов. Повышение антиоксидантной ценности рябинового пюре после СВЧ-нагрева обусловлено изменением содержания антоцианов, флавонолов и катехинов, значения которых увеличиваются соответственно в 3,9, 1,6 и 1,1 раза по сравнению с пюре из свежих плодов и в 1,1, 1,2 и 1,3 раза по сравнению с пюре из бланшированных плодов. При выбранном режиме СВЧ-нагрева быстрее наступает стабилизация окраски пюре из-за инактивации ферментов и в меньшей степени термической деградации антоцианов. Рябиновое пюре, полученное с применением СВЧ-нагрева, рекомендовано при производстве продуктов для здорового и функционального питания, в том числе кондитерских и хлебо-булочных изделий. The Michurinsk State Agrarian University investigated the possibility of using microwave heating in order to increase the antioxidant value of rowan puree. Quercetin was used as a standard for determining the total antioxidants content on the Tsvet Yauza 01-AA device. It was found that with an increase in the microwave heating temperature of rowan fruits to 70 °C, an increase in the total antioxidants content is observed. An increase in the content of antioxidants in a free state is due to changes in cellular structures occurring as a result of microwave heating of rowan. The optimal microwave heating mode for rowan fruits was established: time - 80 seconds, power - 700 W, specific work - 560 W / g·s, at which is ensured the maximum increase of total antioxidants content to 131.9 mg / 100 g (507.3 mg / 100 g dry matter) and a dry matter content of 26.2 %, which is 1.5 and 1.4 times more compared to fresh and blanched fruit puree. An increase in the antioxidant value of rowan puree after microwave heating is due to a change in the content of anthocyanins, flavonols and catechins, the value of which increases by 3.9, 1.6, 1.1 times, respectively, compared with fresh fruit puree and by 1.1, 1.2, 1.3 times compared to blanched fruit puree. With the selected microwave heating mode, the stabilization of the puree color occurs faster due to inactivation of enzymes and a lesser degree of thermal degradation of anthocyanins. Rowan puree obtained using microwave heating is recommended for the production of products for healthy and functional nutrition, including confectionery and bakery products.