Chemical, sensory, and functional properties of whey-based popsicles manufactured with watermelon juice concentrated at different temperatures

Vacuum Concentration Improves the Quality and Antioxidant Capacity of Pear Paste

A vacuum concentration method was established to produce pear paste using fresh pear juice in this study. The optimal condition was determined by comparing the quality indexes, contents of total phenol and flavonoid, and antioxidant properties of the pear paste produced by traditional heating concentration and vacuum concentration. Electronic nose and electronic tongue were introduced in this study to provide digital smell and taste indicators. The results showed that the best vacuum concentration temperature was 65°C, which led to the best sensory evaluation score and pear paste quality. The browning degree and soluble quinones were the lowest in all tested temperatures, and the content were 60.12% and 72.88% compared with the heating method, respectively. While the values were 148.29%, 209.44%, 310.86%, 120.37%, 106.24%, and 181.26% of total phenol, total flavonoid, vitamin C, 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) and hydroxyl (·OH) radical scavenging rates, and total reducing power, respectively. The electronic nose could effectively distinguish the vacuum-concentrated pear paste from the traditional heating-concentration pear paste and could provide quality guidance on their flavor differences through characteristic sensors. The electronic tongue tests showed that the vacuum-concentrated pear paste had larger freshness and richness kurtosis. The pear paste made by the optimized vacuum concentration method had higher retention of nutritional and functional components and higher antioxidant capacity, which could be clearly differentiated from the traditional process, thus this method had an applicable potential.

Manufacturing and characterization of whey and stevia-based popsicles enriched with concentrated beetroot juice

The beet-root (Beta vulgaris) and whey powder together, can potentially use as a multifunctional ingredient in the manufacturing of the "Popsicles", due to their biochemical composition that can enhance the concentration of bioactive compounds. In the present study, beet-root juice concentrates were prepared at different time/temperature treatments viz 45 °C, 55 °C, and 65 °C for 120, 80 and 45 min. The effect of different time/temperature treatments on physicochemical composition, colour, antioxidant activity (%), bioactive compounds, spectral data and sensory acceptance were evaluated. The physicochemical parameters of popsicles (PTI, PT2, PT3) including protein, total phenols, betalain, radical scavenging activity %, colour and melting values were significantly affected (p ≤ 0.05) by the different time/temperature treatments. The concentration of betalain and protein in all the popsicles ranged from 1134 to 1299 mg/L and 1.92 to 1.54 g/100 g respectively. The reduction of bioactive components viz betacyanins, betaxanthins, betanin, oxalic and syringic acid was also observed in popsicle (PTI) as compared to control. Furthermore, popsicle (PT1) was prepared with beet-root juice concentrated at 45 °C showed maximum sensory acceptance. The physicochemical and organoleptic attributes of processed popsicles encourage the commercial usage of whey powder and concentrated beetroot juice.

Current state of the art biotechnological strategies for conversion of watermelon wastes residues to biopolymers production: A review

Poly-3-hydroxyalkanoates (PHA) are biodegradable and compostable polyesters. This review is aimed to provide a unique approach that can help think tanks to frame strategies aiming for clean technology by utilizing cutting edge biotechnological advances to convert fruit and vegetable waste to biopolymer. A PHA manufacturing method based on watermelon waste residue that does not require extensive pretreatment provides a more environmentally friendly and sustainable approach that utilizes an agricultural waste stream. Incorporating fruit processing industry by-products and water, and other resource conservation methods would not only make the manufacturing of microbial bio-plastics like PHA more eco-friendly, but will also help our sector transition to a bioeconomy with circular product streams. The final and most critical element of this review is an in-depth examination of the several hazards inherent in PHA manufacturing.

Freeze concentrated apple juice maintains its flavor

Concentrated juices are sources of alcoholic drinks. Juice concentration may be achieved using different methods, such as freezing or heating. High temperatures in the process of juice concentration damage heat-sensitive components, such as aromatic compounds. Although the freezing process of juice concentration has been studied, analyses have been inadequate, particularly in addressing flavors. Therefore, we investigated the characteristics of freezing and heating during apple juice concentration in the context of flavor. We found that a total of 97 compounds were found in fresh juice, and freeze-concentrated juice retained 57 of these compounds. Interestingly, freezing led to the generation of 37 flavor compounds. Furthermore, people had difficultly differentiating between intact and frozen concentrated juice. The ratios were almost same between those who correctly identified (28%) and those who incorrectly identified fresh and reconstituted freeze-concentrated juice (25%). We discuss the mechanisms of flavor generation on freezing concentration with regard to the increases in enzymatic activity or other causes. Our study showed that the methods of juice concentration that utilize freezing retain flavor better. These data will benefit juice concentration processes of apples and other fruits in the future.

Evaluation of concentration process of bovine, goat and buffalo whey proteins by ultrafiltration

In this research, the protein concentration, the permeate flux, and the predominant fouling mechanisms were investigated during ultrafiltration of different whey samples. The research was carried out at different values of transmembrane pressure and temperature using an experimental design, and a protein concentration of approximately 37 g L-1 was obtained for the bovine whey powder solution, at 60 kPa and 40 °C. The maximum flux observed was 8.9 and 7.9 kg m-2 h-1, respectively, for the bovine whey powder solution and bovine whey, at 50 kPa and 30 °C. Although goat and buffalo whey presented lower permeate flux, probably due to high solutes and calcium contents, protein concentrates of around 40 g L-1 were obtained using the ultrafiltration process. This demonstrates the potential of ultrafiltration to obtain non-bovine protein concentrates. The best fit, verified by Ho and Zydney model, suggests that the fouling for all analyzed whey occurs due to pore blocking and subsequent deposit on the membrane surface.

SPME-GC-MS and Multivariate Analysis of Sensory Properties of Cheese in a Sack Matured with Probiotic Starter Cultures

RESEARCH BACKGROUND

Cheese in a sack is a traditional cheese produced in Croatia. Types of cheese with similar production technology are made in other countries but chemical and microbiological composition varies between regions. Traditionally, cheese in a sack is produced without the addition of starter cultures. Addition of beneficial probiotic cultures to numerous dairy products has documented advantages. Effects that the addition of probiotic bacteria to traditional cheese have on aroma compounds and sensory properties have not been fully investigated. The aim of this study is to determine the sensory properties and differences in the aromatic profiles between cheese samples ripened in a lambskin sack, produced traditionally without the addition of any starter culture, or with the addition of probiotic bacteria.

EXPERIMENTAL APPROACH

In this study, cheese in a sack was produced with the addition of probiotic cultures Lactobacillus plantarum B and L. lactis ssp. lactis S1. During ripening volatile aroma compounds were analysed with a solid-phase microextraction gas chromatography-mass spectrometry. Sensory properties were evaluated by trained tasters who are familiar with the traditional taste of the cheese from a sack. The results of aroma composition and taste scores were then compared using factorial and principal component analyses.

RESULTS AND CONCLUSIONS

Chromatography showed differences in the composition of aroma compounds and the sensory properties between the cheese produced with Lactobacillus starter cultures and the control cheese, traditionally produced without a starter culture. The addition of probiotic cultures L. plantarum B and L. lactis ssp. lactis S1 resulted in products with better sensory properties and chemical profile of volatile aromatic compounds.

NOVELTY AND SCIENTIFIC CONTRIBUTION

This study investigates the usage of naturally present probiotic cultures as starter cultures in cheese in a sack production. Their effects on aroma profiles and sensory characteristics have been compared for the first time using factorial and principal component analyses.

Quality Evaluation of Tigernut Milk-Based Popsicles Produced with Date Palm Fruits as Sweetener

Popsicle is a flavored and edible ice on stick that can be produced with dairy products. This study aimed to investigate the possibility of using milk from tigernut as a non-dairy source and date palm fruits as sweetener for producing popsicles with enhanced bioactive properties and acceptability. Tigernut milk-based popsicles sweetened with sugar, unroasted date or roasted date were made. The physical properties, antioxidant activity, total phenolic content, melting rate, and sensory characteristics were evaluated. The roasting process significantly influenced the total phenol, antioxidant activity and sensory characteristics of the popsicles. Melting resistance was higher in the popsicles containing both the roasted and unroasted dates compared to the sugar sweetened popsicles. Popsicles sweetened with roasted dates exhibited the most acceptable sensory properties in terms of flavour, taste and overall acceptability.

Influence of multiple environmental factors on the quality and flavor of watermelon juice

Environmental factors (heat, pH, oxygen, light) can induce significant quality changes in watermelon juice during processing. To ascertain the effect of such factors on the quality of watermelon juice, the total soluble solids (TSSs), turbidity, lycopene content, color, and flavor were evaluated during different treatments. The pH had a slight impact on the content of lycopene, but had an obvious impact on turbidity. Heat, oxygen, and illumination had considerable effects on the color of watermelon juice, and the results were visible. The content of aldehydes [hexanal, nonanal, (E)-2-noneal, (Z)-6-nonenal] and ketones (6-methyl-5-hepten-2-one, geranylacetone, β-ionone) decreased in treated watermelon juices, while those of 1-nonanol, (Z)-3-nonen-1-ol and (E,Z)-3,6-nonadien-ol increased during illumination. The order of influence of environmental factors on watermelon-juice quality was light > pH > oxygen > heat.